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TDMS Study 05150-02 Pathology Tables

NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97
Route: DOSED FEED                                                                                                 Time: 11:53:50




       Facility:  TSI Mason Research

       Chemical CAS #:  298-59-9

       Lock Date:  02/19/92

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All






































                                                              Page   1

NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 4| 7| 2| 0| 6| 7| 7| 7| 7| 4| 4| 7| 7| 6| 7| 4| 7| 4| 2| 7| 7| 2| 4| 7|             
                             DAY ON TEST   | 5| 5| 4| 8| 6| 2| 4| 4| 4| 4| 5| 5| 4| 4| 7| 4| 5| 4| 5| 8| 4| 4| 8| 5| 4|             
                                           | 6| 5| 7| 1| 7| 8| 6| 7| 7| 7| 5| 5| 7| 6| 3| 7| 5| 7| 6| 0| 7| 7| 0| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                2     3  3  4        2  3  3        2        2  2        4|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Autolysis                            |                3                                                         |             
      Basophilic Focus                     |                      X  X                                                |             
      Congestion                           |             2                                                            |             
      Eosinophilic Focus                   |                                                                          |             
      Fatty Change                         |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Necrosis, Focal                      |    2           1                                1                        |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                         +|             
      Fat, Necrosis                        |                                                                         3|             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                          2               |             
      Duct, Ectasia                        |                                                    4                     |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |    2                                                     2           2   |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Abscess                              |                                                                          |             
      Diverticulum                         |                                                                          |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Muscularis, Hypertrophy              |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |                +                                                         |             
      Angiectasis                          |                2                                                         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |             1                                                            |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Focal                   |                                                                          |             
      Capsule, Hyperplasia                 |                   2                                                      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   2                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 4| 7| 2| 0| 6| 7| 7| 7| 7| 4| 4| 7| 7| 6| 7| 4| 7| 4| 2| 7| 7| 2| 4| 7|             
                             DAY ON TEST   | 5| 5| 4| 8| 6| 2| 4| 4| 4| 4| 5| 5| 4| 4| 7| 4| 5| 4| 5| 8| 4| 4| 8| 5| 4|             
                                           | 6| 5| 7| 1| 7| 8| 6| 7| 7| 7| 5| 5| 7| 6| 3| 7| 5| 7| 6| 0| 7| 7| 0| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                   3                    3                 1               |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  M  +  M  M  +  +  M  +  +  M  M  M  M  +  +  M  +  +  M  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |                2           4        2                       2           2|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia, Focal  |                                     1                                    |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |       M        +  +  +  +  +        +  +  +  +     +        +  M        +|             
      Cyst                                 |                                                                          |             
      Dilatation                           |                3                                   3                     |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +|             
      Cyst                                 |                                           X  X              X            |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                    3                     |             
      Hydrometra                           |                      4           2                                       |             
      Inflammation, Suppurative            |                                                                          |             
      Endometrium, Hyperplasia, Cystic     | 2  2  4  3     1  4  1  2  4  2  3  4  3  4  2  1  3  3     4  4  3  2   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                                          |             
      Myelofibrosis                        |                2  3  1     2                          1     1  4     2   |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                      +                                                   |             
      Lumbar, Hematopoietic Cell           |                                                                          |             
          Proliferation                    |                                                                          |             
      Mediastinal, Hyperplasia, Lymphoid   |                                                                          |             
      Pancreatic, Hyperplasia, Lymphoid    |                                                                          |             
      Renal, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                            4                                             |             
      Depletion Lymphoid                   |             4                                                            |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page   3                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 4| 7| 2| 0| 6| 7| 7| 7| 7| 4| 4| 7| 7| 6| 7| 4| 7| 4| 2| 7| 7| 2| 4| 7|             
                             DAY ON TEST   | 5| 5| 4| 8| 6| 2| 4| 4| 4| 4| 5| 5| 4| 4| 7| 4| 5| 4| 5| 8| 4| 4| 8| 5| 4|             
                                           | 6| 5| 7| 1| 7| 8| 6| 7| 7| 7| 5| 5| 7| 6| 3| 7| 5| 7| 6| 0| 7| 7| 0| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Congestion                           |                                              2                           |             
      Depletion Lymphoid                   |             2                                                            |             
      Hematopoietic Cell Proliferation     |       3                             2              3                     |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  M  M  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |             4                                                            |             
      Hyperplasia, Lymphoid                |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Lactation                            |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                                                          |             
      Mineralization, Focal                |                                                          1               |             
      Mineralization                       | 2  1  2        2  1  1  2     1     2  1        2  2        2  2        2|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |             2                                                            |             
      Hemorrhage, Focal                    |                                                                          |             
      Inflammation, Chronic                |                                           3                              |             
      Peribronchial, Inflammation, Chronic |                                                          2               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |          2                                               1        2      |             
      Inflammation, Chronic, Focal         |          2                                               2        2      |             
      Inflammation, Chronic                | 2  2  2     2  2  2  2  2  2  2  2  2  2  2  2  2  2           2     2  2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                        +                                 |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                      +                                                   |             
      Hyperplasia                          |                      2                                                   |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fatty Change                         |                      2                             2                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   4                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 4| 7| 2| 0| 6| 7| 7| 7| 7| 4| 4| 7| 7| 6| 7| 4| 7| 4| 2| 7| 7| 2| 4| 7|             
                             DAY ON TEST   | 5| 5| 4| 8| 6| 2| 4| 4| 4| 4| 5| 5| 4| 4| 7| 4| 5| 4| 5| 8| 4| 4| 8| 5| 4|             
                                           | 6| 5| 7| 1| 7| 8| 6| 7| 7| 7| 5| 5| 7| 6| 3| 7| 5| 7| 6| 0| 7| 7| 0| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Glomerulosclerosis                   |                                           3                              |             
      Hemorrhage, Focal                    |                3                                                         |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infarct                              |                                                                          |             
      Mineralization                       |                                                    4                     |             
      Renal Tubule, Degeneration, Granular |                                                                          |             
      Renal Tubule, Regeneration           |                         2              1                                 |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |          2                       2              2        2        1  2   |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   5                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 7| 5| 7| 3| 2| 7| 7| 7| 5| 7| 2| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 8| 4| 4| 7| 4| 4| 8| 4| 4| 4| 8| 4| 8| 0| 4| 0| 4| 4| 0| 2| 4| 8| 4| 4| 4|             
                                           | 1| 7| 7| 1| 7| 8| 0| 7| 7| 7| 1| 7| 0| 8| 7| 8| 7| 7| 8| 1| 7| 5| 7| 7| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Hyperplasia, Lymphoid                |       4     4        3  2  3           3        3  3  4  2        2      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                        1                                 |             
      Autolysis                            |                                                                          |             
      Basophilic Focus                     |                                                                          |             
      Congestion                           |                                                                          |             
      Eosinophilic Focus                   |                                                                          |             
      Fatty Change                         |                                                                          |             
      Hematopoietic Cell Proliferation     |                               2                                          |             
      Hyperplasia, Lymphoid                |                                              2                           |             
      Necrosis, Focal                      |          2           1                                                   |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                   +      |             
      Fat, Necrosis                        |                                                                   3      |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         | 1                                                                        |             
      Duct, Ectasia                        |                                                             4            |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Abscess                              |                                                                          |             
      Diverticulum                         |                                                                          |             
      Ulcer                                |                               4                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Muscularis, Hypertrophy              |                                  3                                       |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                        +           +                     |             
      Angiectasis                          |                                        3           3                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hematopoietic Cell Proliferation     |                               3                                          |             
      Hyperplasia, Focal                   |                                                             1            |             
      Capsule, Hyperplasia                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   6                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 7| 5| 7| 3| 2| 7| 7| 7| 5| 7| 2| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 8| 4| 4| 7| 4| 4| 8| 4| 4| 4| 8| 4| 8| 0| 4| 0| 4| 4| 0| 2| 4| 8| 4| 4| 4|             
                                           | 1| 7| 7| 1| 7| 8| 0| 7| 7| 7| 1| 7| 0| 8| 7| 8| 7| 7| 8| 1| 7| 5| 7| 7| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                            1                                         3   |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  M  +  M  +  M  M  I  +  +  +  +  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Pars Distalis, Angiectasis           |                                           1                              |             
      Pars Distalis, Hyperplasia, Focal    |                      4     1     2     2              2     3           2|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia, Focal  |                                        1                                 |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                         +                                                |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |    +  +  +  +        +  +  +  +  +     M  +  +  +  M  M  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +|             
      Cyst                                 |             X           X                                                |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hydrometra                           |                               4                       4                  |             
      Inflammation, Suppurative            |                               4                                          |             
      Endometrium, Hyperplasia, Cystic     | 3  3  3  3  4  1  1  2  3  4  1  3  3  4  3     3  4  1     3     3  2  3|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                               4                                          |             
      Myelofibrosis                        |       2     2           1  1     1     1  3  1     2  4     1     1     1|             
                                            __________________________________________________________________________|             
   Lymph Node                              |                         +     +                          +               |             
      Lumbar, Hematopoietic Cell           |                                                                          |             
          Proliferation                    |                               4                                          |             
      Mediastinal, Hyperplasia, Lymphoid   |                                                                          |             
      Pancreatic, Hyperplasia, Lymphoid    |                         4                                                |             
      Renal, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                               4                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                               4                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Inflammation, Chronic                |                                                       4                  |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page   7                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 7| 5| 7| 3| 2| 7| 7| 7| 5| 7| 2| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 8| 4| 4| 7| 4| 4| 8| 4| 4| 4| 8| 4| 8| 0| 4| 0| 4| 4| 0| 2| 4| 8| 4| 4| 4|             
                                           | 1| 7| 7| 1| 7| 8| 0| 7| 7| 7| 1| 7| 0| 8| 7| 8| 7| 7| 8| 1| 7| 5| 7| 7| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                               4                    1           4         |             
      Hyperplasia, Lymphoid                |                            3                                             |             
                                            __________________________________________________________________________|             
   Thymus                                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Lactation                            |                                              X                           |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |    +                                                                     |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                              4                           |             
      Mineralization, Focal                |                                                                          |             
      Mineralization                       |    2     2  3        1     2     2           2  1     2  1  2  2  2  2  3|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                               4                                          |             
      Inflammation, Chronic                |                                                                          |             
      Peribronchial, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                   2                 2                                    |             
      Inflammation, Chronic, Focal         | 1                 2                 2                                    |             
      Inflammation, Chronic                |    2  2  2  2  2     2  2  2  2  2     2  2  2     2  2  2  2  2  2  2  2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fatty Change                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   8                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 7| 5| 7| 3| 2| 7| 7| 7| 5| 7| 2| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 8| 4| 4| 7| 4| 4| 8| 4| 4| 4| 8| 4| 8| 0| 4| 0| 4| 4| 0| 2| 4| 8| 4| 4| 4|             
                                           | 1| 7| 7| 1| 7| 8| 0| 7| 7| 7| 1| 7| 0| 8| 7| 8| 7| 7| 8| 1| 7| 5| 7| 7| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    0 PPM                                  | 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Glomerulosclerosis                   |                               3                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infarct                              |                                                                          |             
      Mineralization                       |                                                                          |             
      Renal Tubule, Degeneration, Granular |                                                          3               |             
      Renal Tubule, Regeneration           |             2                                                     1      |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  A  +  +  +|             
      Inflammation, Chronic, Focal         |                                     1                                    |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   9                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 4| 7| 2| 4| 2| 2| 7| 7| 2| 6| 7| 7| 7| 7| 7| 7| 7|                 |            |
                             DAY ON TEST   | 5| 4| 5| 4| 8| 5| 8| 8| 4| 4| 8| 8| 4| 4| 4| 4| 4| 4| 4|                 |            |
                                           | 6| 7| 6| 7| 0| 5| 1| 1| 7| 7| 0| 4| 7| 7| 7| 7| 7| 7| 7|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                 |      A     |
    0 PPM                                  | 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  64        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Hyperplasia, Lymphoid                |          2              2  2        2  3     3  2     4                  |     30  2.8|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Angiectasis                          |                                                                          |      1  1.0|
      Autolysis                            |                                                                          |      1  3.0|
      Basophilic Focus                     |                                                                          |      2     |
      Congestion                           |                                                                          |      1  2.0|
      Eosinophilic Focus                   |          X                                X  X                           |      3     |
      Fatty Change                         |                                                    2                     |      1  2.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Hyperplasia, Lymphoid                |                            2                                             |      2  2.0|
      Necrosis, Focal                      |    1     1                                                               |      7  1.3|
                                            __________________________________________________________________________|____________|
   Mesentery                               |          +                 +                    +     +                  |   6        |
      Fat, Necrosis                        |                            3                    3     2                  |      5  2.8|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Inflammation, Chronic, Focal         |                                                                          |      2  1.5|
      Duct, Ectasia                        |                                                                          |      2  4.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Inflammation, Chronic, Focal         |       2        3     2                                                   |      6  2.2|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +                  |  67        |
      Abscess                              |                                           3                              |      1  3.0|
      Diverticulum                         |             3                                                            |      1  3.0|
      Ulcer                                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Muscularis, Hypertrophy              |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   3        |
      Angiectasis                          |                                                                          |      3  2.7|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  10                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 4| 7| 2| 4| 2| 2| 7| 7| 2| 6| 7| 7| 7| 7| 7| 7| 7|                 |            |
                             DAY ON TEST   | 5| 4| 5| 4| 8| 5| 8| 8| 4| 4| 8| 8| 4| 4| 4| 4| 4| 4| 4|                 |            |
                                           | 6| 7| 6| 7| 0| 5| 1| 1| 7| 7| 0| 4| 7| 7| 7| 7| 7| 7| 7|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                 |      A     |
    0 PPM                                  | 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Congestion                           |                                                                          |      1  1.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  3.0|
      Hyperplasia, Focal                   |                                                                          |      1  1.0|
      Capsule, Hyperplasia                 |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Hyperplasia, Focal                   |                                                       2                  |      1  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Hyperplasia                          |          2                                            4                  |      7  2.4|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  +  M  M  M  M  +  +  M  M  +  +  +  +  +  +  +                  |  43        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Pars Distalis, Angiectasis           |                                                                          |      1  1.0|
      Pars Distalis, Hyperplasia, Focal    |    3                                   4                                 |     14  2.5|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Follicular Cell, Hyperplasia, Focal  |                                                 2  1                     |      4  1.3|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |    +                                                                     |   2        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |    +     +  +           +  +     +  +  +  +  +  +  +  +                  |  43        |
      Cyst                                 |             X                                                            |      1     |
      Dilatation                           |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Cyst                                 |                X                    X                                    |      7     |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Angiectasis                          |                                                                          |      1  3.0|
      Hydrometra                           |                2        4                                                |      6  3.3|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
      Endometrium, Hyperplasia, Cystic     | 1  1  1  1  2  1  1  1  3  1  3  1  2  3  3  3  2  2  4                  |     63  2.5|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Hyperplasia, Neutrophil              |          2                                                               |      2  3.0|
      Myelofibrosis                        |       1                             2           2     2                  |     25  1.8|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                  +  +     +                              |   7        |
      Lumbar, Hematopoietic Cell           |                                                                          |            |
          Proliferation                    |                                                                          |      1  4.0|
      Mediastinal, Hyperplasia, Lymphoid   |                                     4                                    |      1  4.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  11                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 4| 7| 2| 4| 2| 2| 7| 7| 2| 6| 7| 7| 7| 7| 7| 7| 7|                 |            |
                             DAY ON TEST   | 5| 4| 5| 4| 8| 5| 8| 8| 4| 4| 8| 8| 4| 4| 4| 4| 4| 4| 4|                 |            |
                                           | 6| 7| 6| 7| 0| 5| 1| 1| 7| 7| 0| 4| 7| 7| 7| 7| 7| 7| 7|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                 |      A     |
    0 PPM                                  | 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Pancreatic, Hyperplasia, Lymphoid    |                                                                          |      1  4.0|
      Renal, Hematopoietic Cell            |                                                                          |            |
          Proliferation                    |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Hematopoietic Cell Proliferation     |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Congestion                           |                                                                          |      1  4.0|
      Depletion Lymphoid                   |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Congestion                           |                                                                          |      1  2.0|
      Depletion Lymphoid                   |                                                                          |      1  2.0|
      Hematopoietic Cell Proliferation     |    3     4                                                               |      8  3.0|
      Hyperplasia, Lymphoid                |                                                       2                  |      2  2.5|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Depletion Lymphoid                   |                                                                          |      1  4.0|
      Hyperplasia, Lymphoid                |                                     4                                    |      2  3.5|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  M  +  +  M  +  M  +  +  +  +  M  +  M  +  +  +                  |  59        |
      Lactation                            |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Ulcer                                |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Compression                          |                                                                          |      1  4.0|
      Mineralization, Focal                |                               2                                          |      2  1.5|
      Mineralization                       |    2  2  3     2        1  2     3  3  2  2  3        1                  |     42  1.9|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Congestion                           |                                                                          |      1  2.0|
      Hemorrhage, Focal                    |                                     2                                    |      2  3.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  12                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 4| 7| 2| 4| 2| 2| 7| 7| 2| 6| 7| 7| 7| 7| 7| 7| 7|                 |            |
                             DAY ON TEST   | 5| 4| 5| 4| 8| 5| 8| 8| 4| 4| 8| 8| 4| 4| 4| 4| 4| 4| 4|                 |            |
                                           | 6| 7| 6| 7| 0| 5| 1| 1| 7| 7| 0| 4| 7| 7| 7| 7| 7| 7| 7|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                 |      A     |
    0 PPM                                  | 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Peribronchial, Inflammation, Chronic |                   1  1                                                   |      3  1.3|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Degeneration, Hyaline                |             2     2           2                                          |      8  1.9|
      Inflammation, Chronic, Focal         |             2     2  2        2                                          |     10  1.9|
      Inflammation, Chronic                | 2  2  2  2              2  2     3  2     2  1  2  2  2                  |     54  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                     +                                    |   2        |
      Hyperplasia                          |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Fatty Change                         |                                                                          |      2  2.0|
      Glomerulosclerosis                   |                                                                          |      2  3.0|
      Hemorrhage, Focal                    |                                                                          |      1  3.0|
      Hyperplasia, Lymphoid                |                            1                                             |      1  1.0|
      Infarct                              |          2                       3                                       |      2  2.5|
      Mineralization                       |                                                                          |      1  4.0|
      Renal Tubule, Degeneration, Granular |                                                                          |      1  3.0|
      Renal Tubule, Regeneration           |                                     1  1              1                  |      7  1.3|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +                  |  63        |
      Inflammation, Chronic, Focal         |                2                                                         |      8  1.8|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  13                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 4| 7| 7| 2| 7| 7| 4| 4| 2| 7| 7| 7| 7| 2| 7| 0| 6| 2| 7| 7| 7| 4| 4| 4|             
                             DAY ON TEST   | 9| 5| 4| 4| 8| 4| 4| 5| 5| 8| 4| 4| 4| 4| 8| 4| 1| 8| 8| 4| 4| 4| 6| 5| 5|             
                                           | 9| 6| 3| 3| 1| 3| 3| 5| 5| 1| 3| 3| 3| 1| 0| 3| 2| 1| 1| 3| 3| 6| 2| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    50 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +     M  +  +  +  +  +  +  +|             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |       3        4                 3     2     3           3     2  2      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     | X                                                        X     X         |             
      Clear Cell Focus                     |                                                                          |             
      Eosinophilic Focus                   |                                                                X         |             
      Fatty Change                         |                                                                          |             
      Hematopoietic Cell Proliferation     | 2                                                                        |             
      Hemorrhage                           |                                                          2               |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Necrosis, Focal                      |    2                                                                 2   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                         2|             
      Acinus, Atrophy                      |                                        4                                 |             
      Duct, Ectasia                        |                                                          3               |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |    2        2           2                 2                             2|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Edema                                |                                                                          |             
      Erosion                              |                                        3                                 |             
      Inflammation, Chronic                |       2                                                                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Cytoplasmic Alteration, Focal        |                                                                          |             
      Hypertrophy                          |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +     +  I  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 4           3                                         3                  |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  14                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 4| 7| 7| 2| 7| 7| 4| 4| 2| 7| 7| 7| 7| 2| 7| 0| 6| 2| 7| 7| 7| 4| 4| 4|             
                             DAY ON TEST   | 9| 5| 4| 4| 8| 4| 4| 5| 5| 8| 4| 4| 4| 4| 8| 4| 1| 8| 8| 4| 4| 4| 6| 5| 5|             
                                           | 9| 6| 3| 3| 1| 3| 3| 5| 5| 1| 3| 3| 3| 1| 0| 3| 2| 1| 1| 3| 3| 6| 2| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    50 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  +  +  +  +  +  +  +  +  +  M  M  M  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    | 4              4                    3        3     3                     |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Follicular Cell, Hyperplasia, Focal  | 2     2  3        2                                                      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +     +  M     +  +           +  +  M  +     +     +     +  +  +  +      |             
      Dilatation                           |                4                                                         |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Cyst                                 |          X                                               X               |             
      Mineralization, Focal                |                                                                          |             
      Thrombosis                           |    X                                                                     |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hydrometra                           |                                                             3            |             
      Endometrium, Hyperplasia, Cystic     | 3  1  3  4  1  3  3  1  1  3  3  3  2  3  2  3     1     2  1  4     2  2|             
      Endometrium, Metaplasia, Squamous    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              | 4                                                  2                     |             
      Myelofibrosis                        |       2  2     3              2  2                       2  1  1         |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                               +                    +                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +     M  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphatic, Angiectasis               |                               3                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     | 4  2                                                                     |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Necrosis, Focal                      |                                        3                                 |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +     +  +  +  +  +  +  +  +|             
      Lactation                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  15                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 4| 7| 7| 2| 7| 7| 4| 4| 2| 7| 7| 7| 7| 2| 7| 0| 6| 2| 7| 7| 7| 4| 4| 4|             
                             DAY ON TEST   | 9| 5| 4| 4| 8| 4| 4| 5| 5| 8| 4| 4| 4| 4| 8| 4| 1| 8| 8| 4| 4| 4| 6| 5| 5|             
                                           | 9| 6| 3| 3| 1| 3| 3| 5| 5| 1| 3| 3| 3| 1| 0| 3| 2| 1| 1| 3| 3| 6| 2| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    50 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hemorrhage, Focal                    |                                                                          |             
      Mineralization                       | 2  2  3  2     1        2     3  2  3  2     2     1     1     2     1  1|             
      Artery, Inflammation, Chronic        |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
      Artery, Inflammation, Chronic        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                                                                2         |             
      Thrombosis                           |                                                                          |             
      Peribronchial, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |             2                             2           2                  |             
      Inflammation, Chronic, Focal         |             2              2                          2                  |             
      Inflammation, Chronic                |    2  2  2     3  2  2  2     2  2  2  2     2           2  2  2  2     2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                  +                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Renal Tubule, Necrosis               |                                                                          |             
      Renal Tubule, Regeneration           |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +     +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |    1                 2  2                             2                 1|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  16                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 7| 7| 7| 6| 4| 5| 7| 7| 7| 7| 7| 7| 1| 7| 7| 6| 2| 7| 3| 4| 6| 1| 7|             
                             DAY ON TEST   | 4| 8| 4| 4| 4| 2| 5| 8| 4| 4| 4| 4| 4| 4| 0| 4| 4| 0| 8| 4| 9| 5| 9| 5| 4|             
                                           | 6| 1| 6| 6| 3| 5| 5| 8| 3| 6| 6| 6| 6| 6| 3| 6| 6| 3| 1| 6| 1| 5| 0| 8| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    50 PPM                                 | 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1|             
                                           | 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  A  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +|             
      Hyperplasia, Lymphoid                | 4        4              4  2  3  3                                       |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |       X                                                                  |             
      Clear Cell Focus                     |                               X                          X               |             
      Eosinophilic Focus                   |             X                                X                           |             
      Fatty Change                         |                                                                   3      |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hemorrhage                           |                                                                          |             
      Hyperplasia, Lymphoid                |                                     1                                    |             
      Necrosis, Focal                      |                   2                                            2         |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                2         |             
      Acinus, Atrophy                      |                                                                          |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |    1                                                                     |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Edema                                |                                                                   2      |             
      Erosion                              |                2                                                         |             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic        |                                                             3            |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cytoplasmic Alteration, Focal        |          3                 4                                             |             
      Hypertrophy                          |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          2        1                                   2  2               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  17                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 7| 7| 7| 6| 4| 5| 7| 7| 7| 7| 7| 7| 1| 7| 7| 6| 2| 7| 3| 4| 6| 1| 7|             
                             DAY ON TEST   | 4| 8| 4| 4| 4| 2| 5| 8| 4| 4| 4| 4| 4| 4| 0| 4| 4| 0| 8| 4| 9| 5| 9| 5| 4|             
                                           | 6| 1| 6| 6| 3| 5| 5| 8| 3| 6| 6| 6| 6| 6| 3| 6| 6| 3| 1| 6| 1| 5| 0| 8| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    50 PPM                                 | 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1|             
                                           | 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  M  +  M  +  +  M  +  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                            2                                             |             
      Pars Distalis, Hyperplasia, Focal    |                               4              2  3                        |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                             4            |             
      Follicular Cell, Hyperplasia, Focal  |          2  2           4                                                |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +     M  +  +  +     +  +  +  +  +  +  +     +  +  M     +        +     +|             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |          X                 X        X                 X        X         |             
      Mineralization, Focal                |                                                                          |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          | 2                                                        4               |             
      Hydrometra                           | 4     4  3                             4                                 |             
      Endometrium, Hyperplasia, Cystic     | 2  3  2  1  4  1  2  1  2  3  4  3  3  1     3  3  2  3  2     2  2     3|             
      Endometrium, Metaplasia, Squamous    |          3                                                               |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                         2                          3                     |             
      Myelofibrosis                        |       1  2        4        2  1        1     1                           |             
                                            __________________________________________________________________________|             
   Lymph Node                              |       +        +                                                         |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Congestion                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphatic, Angiectasis               |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                      2                                               3   |             
      Hematopoietic Cell Proliferation     | 3     4                 3                 4        4                     |             
      Hyperplasia, Lymphoid                |                                     2                                    |             
      Necrosis, Focal                      |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                      4   |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +|             
      Lactation                            |                         X                                                |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  18                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 7| 7| 7| 6| 4| 5| 7| 7| 7| 7| 7| 7| 1| 7| 7| 6| 2| 7| 3| 4| 6| 1| 7|             
                             DAY ON TEST   | 4| 8| 4| 4| 4| 2| 5| 8| 4| 4| 4| 4| 4| 4| 0| 4| 4| 0| 8| 4| 9| 5| 9| 5| 4|             
                                           | 6| 1| 6| 6| 3| 5| 5| 8| 3| 6| 6| 6| 6| 6| 3| 6| 6| 3| 1| 6| 1| 5| 0| 8| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    50 PPM                                 | 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1|             
                                           | 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage, Focal                    |                3                                                         |             
      Mineralization                       | 2     2  2           3        2     1  2        3        3     2  2     3|             
      Artery, Inflammation, Chronic        |                                                             4            |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                             +            |             
      Artery, Inflammation, Chronic        |                                                             3            |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                                                 4                        |             
      Thrombosis                           |                                                    1                     |             
      Peribronchial, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |    2                                                                     |             
      Inflammation, Chronic, Focal         |    2                                                  2                  |             
      Inflammation, Chronic                | 2        2  2        2  2  2  1  2  2  2  2  2  2  2     2  2  2  2     2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                           3                              |             
      Glomerulosclerosis                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Renal Tubule, Necrosis               |                      4                             3                     |             
      Renal Tubule, Regeneration           |                                  1                                      1|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
      Inflammation, Chronic, Focal         |                                                             3            |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  19                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 4| 4| 6| 2| 7| 7| 7| 7| 7| 1| 7| 2| 2| 7| 7| 6| 7|                 |            |
                             DAY ON TEST   | 4| 5| 5| 5| 2| 8| 4| 4| 4| 4| 4| 4| 4| 8| 8| 4| 4| 9| 3|                 |            |
                                           | 6| 6| 6| 6| 8| 0| 6| 6| 6| 6| 6| 5| 6| 1| 0| 6| 6| 0| 0|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|                 |      A     |
    50 PPM                                 | 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  M  M  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  56        |
      Dilatation                           |                                                       4                  |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  63        |
      Hyperplasia, Lymphoid                |                   3  4     2                 2                           |     18  2.9|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  62        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  63        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  61        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Angiectasis                          |                         2                                                |      1  2.0|
      Basophilic Focus                     |                                                                          |      4     |
      Clear Cell Focus                     |                                                                          |      2     |
      Eosinophilic Focus                   |                                                                          |      3     |
      Fatty Change                         |                                                                          |      1  3.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Hemorrhage                           |                                                                          |      1  2.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  1.0|
      Necrosis, Focal                      |                                                                          |      4  2.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Inflammation, Chronic, Focal         |                                                                          |      2  2.0|
      Acinus, Atrophy                      |                                                                          |      1  4.0|
      Duct, Ectasia                        |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +                  |  67        |
      Inflammation, Chronic, Focal         |       2                                                                  |      7  1.9|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  65        |
      Edema                                |                                                                          |      1  2.0|
      Erosion                              |                                                                          |      2  2.5|
      Inflammation, Chronic                |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Artery, Inflammation, Chronic        |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Cytoplasmic Alteration, Focal        |                                                                          |      2  3.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  20                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 4| 4| 6| 2| 7| 7| 7| 7| 7| 1| 7| 2| 2| 7| 7| 6| 7|                 |            |
                             DAY ON TEST   | 4| 5| 5| 5| 2| 8| 4| 4| 4| 4| 4| 4| 4| 8| 8| 4| 4| 9| 3|                 |            |
                                           | 6| 6| 6| 6| 8| 0| 6| 6| 6| 6| 6| 5| 6| 1| 0| 6| 6| 0| 0|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|                 |      A     |
    50 PPM                                 | 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Hypertrophy                          |                                  2                                       |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  64        |
      Hyperplasia, Focal                   |                                     3                                    |      1  3.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Hyperplasia                          |                      4     2                                             |      9  2.6|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  M  M  M  +  +  M  M  M  M  +  +  +  +  M  M  +                  |  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Pars Distalis, Angiectasis           |                                                                          |      1  2.0|
      Pars Distalis, Hyperplasia, Focal    |                            4  3                                          |     10  3.3|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
      Follicular Cell, Hyperplasia, Focal  | 2                    2     1                 1                           |     11  2.1|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +           +     +  +  +  +  +     +        +  +  +  +                  |  41        |
      Dilatation                           |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Cyst                                 |          X        X     X  X              X           X                  |     13     |
      Mineralization, Focal                |                                           3                              |      1  3.0|
      Thrombosis                           |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Angiectasis                          |                                                 2                        |      3  2.7|
      Hydrometra                           |    2                                         4        4                  |      8  3.5|
      Endometrium, Hyperplasia, Cystic     | 3  2  2  3  3  2  4  3  4  3  4     3  2  2  3  4  1  3                  |     62  2.5|
      Endometrium, Metaplasia, Squamous    |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Hyperplasia, Neutrophil              |                            3                          4                  |      6  3.0|
      Myelofibrosis                        |                   2  1        2     3        1  1                        |     21  1.8|
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +                 +                                +                     |   7        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +                  |  61        |
      Congestion                           |                                        2                                 |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Lymphatic, Angiectasis               |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  21                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 4| 4| 6| 2| 7| 7| 7| 7| 7| 1| 7| 2| 2| 7| 7| 6| 7|                 |            |
                             DAY ON TEST   | 4| 5| 5| 5| 2| 8| 4| 4| 4| 4| 4| 4| 4| 8| 8| 4| 4| 9| 3|                 |            |
                                           | 6| 6| 6| 6| 8| 0| 6| 6| 6| 6| 6| 5| 6| 1| 0| 6| 6| 0| 0|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|                 |      A     |
    50 PPM                                 | 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Depletion Lymphoid                   |                                                    4                     |      3  3.0|
      Hematopoietic Cell Proliferation     |                            3     1                    4                  |     10  3.2|
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
      Necrosis, Focal                      |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  M                  |  66        |
      Depletion Lymphoid                   |                                  4                                       |      2  4.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M                  |  60        |
      Lactation                            | X                                                                        |      2     |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Hyperostosis                         | 2                                                                        |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Hemorrhage, Focal                    |                                                                          |      1  3.0|
      Mineralization                       | 2           2     3  1  3     3     3        2  1     2                  |     38  2.1|
      Artery, Inflammation, Chronic        |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                                                          |   1        |
      Artery, Inflammation, Chronic        |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Congestion                           |                                  3                                       |      1  3.0|
      Hemorrhage, Focal                    |                                                                          |      2  3.0|
      Thrombosis                           |                                                                          |      1  1.0|
      Peribronchial, Inflammation, Chronic |                1                                                         |      1  1.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Degeneration, Hyaline                |                                                                          |      4  2.0|
      Inflammation, Chronic, Focal         |                2                       2  2                              |      8  2.0|
      Inflammation, Chronic                | 2  2  2  2  2     2     2  2        2        2  2  1  2                  |     49  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                  +                                       |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   1        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  22                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 4| 4| 6| 2| 7| 7| 7| 7| 7| 1| 7| 2| 2| 7| 7| 6| 7|                 |            |
                             DAY ON TEST   | 4| 5| 5| 5| 2| 8| 4| 4| 4| 4| 4| 4| 4| 8| 8| 4| 4| 9| 3|                 |            |
                                           | 6| 6| 6| 6| 8| 0| 6| 6| 6| 6| 6| 5| 6| 1| 0| 6| 6| 0| 0|                 |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                 |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|                 |      A     |
    50 PPM                                 | 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|                 |      L     |
                                           | 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|                 |            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Congestion                           |                                                                          |      1  3.0|
      Glomerulosclerosis                   |                                  4                    3                  |      2  3.5|
      Hyperplasia, Lymphoid                |                            2                                             |      1  2.0|
      Renal Tubule, Necrosis               |                                                                          |      2  3.5|
      Renal Tubule, Regeneration           |                                              2                           |      3  1.3|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  A  +  +  +  M  +  +  +  +  +  +  +  +  A  +                  |  59        |
      Inflammation, Chronic, Focal         |       1                                                                  |      7  1.7|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  23                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 4| 2| 7| 7| 7| 4| 7| 6| 7| 7| 0| 7| 7| 7| 7| 7| 7| 6| 1| 2|             
                             DAY ON TEST   | 4| 1| 4| 4| 9| 5| 8| 4| 4| 4| 5| 0| 8| 4| 4| 5| 4| 4| 4| 4| 4| 4| 8| 8| 8|             
                                           | 3| 9| 3| 3| 7| 6| 0| 2| 3| 2| 5| 8| 9| 2| 3| 7| 2| 2| 2| 2| 2| 3| 6| 3| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Edema                                |             3                                                            |             
      Hyperplasia, Lymphoid                |       3  3              3  2        3              2           3  2      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                      4                                                   |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                                                                          |             
      Clear Cell Focus                     |                            X                                             |             
      Eosinophilic Focus                   |       X        X     X              X     X                              |             
      Fatty Change, Focal                  |                                                 1           1            |             
      Fatty Change                         |                                           2        1              1      |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Necrosis, Focal                      |             1  2                                                         |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
      Acinus, Atrophy                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Diverticulum                         |                                                                          |             
      Ulcer                                |       4                                                                  |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                               2                                          |             
      Inflammation, Chronic                |                                                                          |             
      Muscularis, Hypertrophy              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypertrophy                          |                                              2                           |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                           2        2           1         |             
      Hypoplasia                           |                                                                         2|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  24                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 4| 2| 7| 7| 7| 4| 7| 6| 7| 7| 0| 7| 7| 7| 7| 7| 7| 6| 1| 2|             
                             DAY ON TEST   | 4| 1| 4| 4| 9| 5| 8| 4| 4| 4| 5| 0| 8| 4| 4| 5| 4| 4| 4| 4| 4| 4| 8| 8| 8|             
                                           | 3| 9| 3| 3| 7| 6| 0| 2| 3| 2| 5| 8| 9| 2| 3| 7| 2| 2| 2| 2| 2| 3| 6| 3| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Hyperplasia, Focal    |    2     3              3  3           4  2     3              3         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicle, Cyst                       |                         X                                                |             
      Follicular Cell, Hyperplasia, Focal  |                                        1           1                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +        +  +  +     +  +  +  M     +  +  +  +  +  +  +      |             
      Abscess                              |                                                                          |             
      Pigmentation, Hemosiderin            |                                                                2         |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Abscess                              |             4                                                            |             
      Angiectasis                          |                                                                          |             
      Cyst                                 | X           X              X     X                                       |             
      Mineralization, Focal                |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hydrometra                           |          4                             4                                 |             
      Endometrium, Hyperplasia, Cystic     | 4  4  3  2  1  2  3  3  4  2  3  3  2  3  3     4  3  3  3  2  3  2     2|             
      Endometrium, Metaplasia, Squamous    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |             4                                                            |             
      Myelofibrosis                        | 1        2           1  3              2  3     1     2  2        2      |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +  +  +                                                           +   |             
      Lumbar, Lymphatic, Angiectasis       |                                                                          |             
      Mediastinal, Infiltration Cellular,  |                                                                          |             
           Mixed Cell                      |                                                                          |             
      Pancreatic, Hyperplasia, Lymphoid    |       2  1                                                               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Lymphatic, Angiectasis               |             3                                                            |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |          3                                                               |             
      Depletion Lymphoid                   |                                              2                    4      |             
      Hematopoietic Cell Proliferation     |             4                                                  2         |             
      Hyperplasia, Lymphoid                |       2  1                                                               |             
      Necrosis, Focal                      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  25                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 4| 2| 7| 7| 7| 4| 7| 6| 7| 7| 0| 7| 7| 7| 7| 7| 7| 6| 1| 2|             
                             DAY ON TEST   | 4| 1| 4| 4| 9| 5| 8| 4| 4| 4| 5| 0| 8| 4| 4| 5| 4| 4| 4| 4| 4| 4| 8| 8| 8|             
                                           | 3| 9| 3| 3| 7| 6| 0| 2| 3| 2| 5| 8| 9| 2| 3| 7| 2| 2| 2| 2| 2| 3| 6| 3| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |             3                                3                           |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M|             
      Lactation                            |                                     X                                    |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                     3                                    |             
      Mineralization, Focal                |                                                                         1|             
      Mineralization                       |    2  2     2        1  2     2  2     1  2     1        2        1      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage, Focal                    |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Peribronchial, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                   2                                                     2|             
      Inflammation, Chronic, Focal         |                   2                                                     2|             
      Inflammation, Chronic                | 2  2  2  2  2  2     2  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2      |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                  +                    +     +            |             
      Hyperplasia                          |                                                       2                  |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                              2                           |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Nephropathy                          |          2                                                               |             
      Renal Tubule, Degeneration, Granular |                                                                          |             
      Renal Tubule, Regeneration           |                                                          1              1|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  A  +  +  +  +  +  +  +  +  +  +  +  M  +  A  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                   1           1                                         2|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  26                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 2| 5| 4| 7| 7| 6| 7| 2| 2| 7| 2| 7| 7| 4| 7| 4| 2| 4| 4| 7| 7| 7|             
                             DAY ON TEST   | 4| 5| 4| 8| 7| 5| 4| 2| 0| 4| 8| 8| 4| 8| 4| 0| 5| 4| 5| 8| 5| 6| 4| 4| 4|             
                                           | 2| 6| 2| 1| 8| 5| 3| 8| 7| 3| 0| 0| 3| 1| 3| 5| 5| 2| 5| 0| 6| 9| 2| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  A  +  +  M  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Edema                                |                                                                          |             
      Hyperplasia, Lymphoid                | 3                                                                 2  3   |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                    1                     |             
      Basophilic Focus                     |                                              X        X                  |             
      Clear Cell Focus                     |                            X                                             |             
      Eosinophilic Focus                   |                                           X                          X  X|             
      Fatty Change, Focal                  |                                                                          |             
      Fatty Change                         | 1                                               2                        |             
      Hematopoietic Cell Proliferation     |                                                                3  2      |             
      Necrosis, Focal                      |    4        3  1                                                     1   |             
                                            __________________________________________________________________________|             
   Mesentery                               | +                                                                        |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                             2            |             
      Acinus, Atrophy                      |             2                                                            |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                2              2                             2            |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Diverticulum                         |                                           2                              |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Muscularis, Hypertrophy              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypertrophy                          |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  M  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |       3                                                                  |             
      Hypoplasia                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  27                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 2| 5| 4| 7| 7| 6| 7| 2| 2| 7| 2| 7| 7| 4| 7| 4| 2| 4| 4| 7| 7| 7|             
                             DAY ON TEST   | 4| 5| 4| 8| 7| 5| 4| 2| 0| 4| 8| 8| 4| 8| 4| 0| 5| 4| 5| 8| 5| 6| 4| 4| 4|             
                                           | 2| 6| 2| 1| 8| 5| 3| 8| 7| 3| 0| 0| 3| 1| 3| 5| 5| 2| 5| 0| 6| 9| 2| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  M  M  M  M  +  +  M  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Hyperplasia, Focal    | 4  4                                                                 3  3|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicle, Cyst                       |                                                                          |             
      Follicular Cell, Hyperplasia, Focal  | 1     2                             1                                    |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +     +     +  +  A  +        +     +  +     +           +  +  +  +|             
      Abscess                              |                                                                          |             
      Pigmentation, Hemosiderin            |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Abscess                              |                                                                          |             
      Angiectasis                          |                                                                          |             
      Cyst                                 |       X        X     X     X                                         X   |             
      Mineralization, Focal                |                                        4                                 |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hydrometra                           |                                                                      4   |             
      Endometrium, Hyperplasia, Cystic     | 3     3  2        4  1     3  2  2  4  2  4  3  2  2  2  1  2     3  4  3|             
      Endometrium, Metaplasia, Squamous    |                                                                      3   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  A  +  +  +  +  +  +  A  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                      4                                                   |             
      Myelofibrosis                        |       1        1  1                 3     2                          3  1|             
                                            __________________________________________________________________________|             
   Lymph Node                              |             +                             +                              |             
      Lumbar, Lymphatic, Angiectasis       |                                                                          |             
      Mediastinal, Infiltration Cellular,  |                                                                          |             
           Mixed Cell                      |                                                                          |             
      Pancreatic, Hyperplasia, Lymphoid    |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
      Necrosis                             |    4                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  M  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphatic, Angiectasis               | 4                                                                        |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |             4     3  3                             2     3     3         |             
      Hyperplasia, Lymphoid                |                            3                                             |             
      Necrosis, Focal                      |    4                                                                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  28                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 2| 5| 4| 7| 7| 6| 7| 2| 2| 7| 2| 7| 7| 4| 7| 4| 2| 4| 4| 7| 7| 7|             
                             DAY ON TEST   | 4| 5| 4| 8| 7| 5| 4| 2| 0| 4| 8| 8| 4| 8| 4| 0| 5| 4| 5| 8| 5| 6| 4| 4| 4|             
                                           | 2| 6| 2| 1| 8| 5| 3| 8| 7| 3| 0| 0| 3| 1| 3| 5| 5| 2| 5| 0| 6| 9| 2| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    250 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lactation                            |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                                                          |             
      Mineralization, Focal                |                                                                          |             
      Mineralization                       |    3  2        1  2  3     2        1        2  1     2        1  1     2|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage, Focal                    |                            3                                             |             
      Inflammation, Chronic                |                                                                          |             
      Peribronchial, Inflammation, Chronic |          1                             2                 2               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |          2                    2  2     2                                 |             
      Inflammation, Chronic, Focal         |          2                    2  2     2                 2               |             
      Inflammation, Chronic                |       2        2  1  2  2  2        2     2  2     2  2     2  2  2      |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid                |                            2                                             |             
      Infarct                              |                                           3                              |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Degeneration, Granular |             4           4                                                |             
      Renal Tubule, Regeneration           |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                               1        2              1  2  2            |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  29                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 4| 4| 7| 4| 7| 7| 7| 7| 2| 7| 7| 2| 7| 7|              |            |
                             DAY ON TEST   | 5| 4| 8| 4| 4| 4| 5| 5| 4| 5| 4| 4| 4| 4| 8| 4| 4| 8| 4| 4|              |            |
                                           | 5| 2| 1| 2| 2| 2| 5| 6| 3| 6| 3| 2| 2| 2| 1| 3| 3| 0| 2| 2|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|              |      A     |
    250 PPM                                | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  63        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Edema                                |                                                                          |      1  3.0|
      Hyperplasia, Lymphoid                |    2                    1     4        3     2        3  4               |     18  2.7|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Hyperplasia, Lymphoid                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Angiectasis                          |                                                                          |      1  1.0|
      Basophilic Focus                     |                                                 X                        |      3     |
      Clear Cell Focus                     |                                                                          |      2     |
      Eosinophilic Focus                   |                      X                          X                        |     10     |
      Fatty Change, Focal                  |                                                                          |      2  1.0|
      Fatty Change                         |                      1     1              1                              |      8  1.3|
      Hematopoietic Cell Proliferation     |                                                                          |      2  2.5|
      Necrosis, Focal                      |                      2                                                   |      7  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Inflammation, Chronic, Focal         |                                                                          |      1  2.0|
      Acinus, Atrophy                      |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         | 1                    2     2                       2                     |      7  1.9|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Diverticulum                         |                                                                          |      1  2.0|
      Ulcer                                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Inflammation, Chronic, Focal         |                                                                          |      1  2.0|
      Inflammation, Chronic                |                                        2                                 |      1  2.0|
      Muscularis, Hypertrophy              |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  30                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 4| 4| 7| 4| 7| 7| 7| 7| 2| 7| 7| 2| 7| 7|              |            |
                             DAY ON TEST   | 5| 4| 8| 4| 4| 4| 5| 5| 4| 5| 4| 4| 4| 4| 8| 4| 4| 8| 4| 4|              |            |
                                           | 5| 2| 1| 2| 2| 2| 5| 6| 3| 6| 3| 2| 2| 2| 1| 3| 3| 0| 2| 2|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|              |      A     |
    250 PPM                                | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Hypertrophy                          |                                  2                                       |      2  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  66        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia                          |                      1  1     2     2           2        4               |     10  2.0|
      Hypoplasia                           |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  +  M  +  +  +  M  +  +  M  +  +  M               |  53        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +               |  68        |
      Pars Distalis, Hyperplasia, Focal    |                                        3                                 |     13  3.1|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  68        |
      Follicle, Cyst                       |                                        X                                 |      2     |
      Follicular Cell, Hyperplasia, Focal  |             1                          1              3                  |      8  1.4|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |    +     +  M  +        +     +  M  +  +     +  +     +  +               |  44        |
      Abscess                              |                2                                                         |      1  2.0|
      Pigmentation, Hemosiderin            |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Abscess                              |                                                                          |      1  4.0|
      Angiectasis                          |                                  3                                       |      1  3.0|
      Cyst                                 |             X     X              X  X                                    |     13     |
      Mineralization, Focal                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Angiectasis                          |                                     1        3                           |      2  2.0|
      Hydrometra                           |             4                          4              4                  |      6  4.0|
      Endometrium, Hyperplasia, Cystic     | 1  2  2     2     1  2  3  1  3  2  3     3     4     3  3               |     58  2.6|
      Endometrium, Metaplasia, Squamous    |                                                          3               |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Hyperplasia, Neutrophil              |          2                             3              3                  |      5  3.2|
      Myelofibrosis                        |    1                    1     1     1                    2               |     22  1.7|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                        +              +                  |   8        |
      Lumbar, Lymphatic, Angiectasis       |                                                       3                  |      1  3.0|
      Mediastinal, Infiltration Cellular,  |                                                                          |            |
           Mixed Cell                      |                                                       3                  |      1  3.0|
      Pancreatic, Hyperplasia, Lymphoid    |                                                                          |      2  1.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  31                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 4| 4| 7| 4| 7| 7| 7| 7| 2| 7| 7| 2| 7| 7|              |            |
                             DAY ON TEST   | 5| 4| 8| 4| 4| 4| 5| 5| 4| 5| 4| 4| 4| 4| 8| 4| 4| 8| 4| 4|              |            |
                                           | 5| 2| 1| 2| 2| 2| 5| 6| 3| 6| 3| 2| 2| 2| 1| 3| 3| 0| 2| 2|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|              |      A     |
    250 PPM                                | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Necrosis                             |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Lymphatic, Angiectasis               |                               3                                          |      3  3.3|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Congestion                           |                                                                          |      1  3.0|
      Depletion Lymphoid                   |    1                                                                     |      3  2.3|
      Hematopoietic Cell Proliferation     |          3     4        2     3        4                                 |     13  3.1|
      Hyperplasia, Lymphoid                |                                              2                           |      4  2.0|
      Necrosis, Focal                      |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  67        |
      Depletion Lymphoid                   |                                                                          |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +               |  63        |
      Lactation                            |                                        X              X                  |      3     |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Compression                          |                                                                          |      1  3.0|
      Mineralization, Focal                |                                                                          |      1  1.0|
      Mineralization                       | 2  2     3  2  2           1     2  2        2        2  1               |     36  1.8|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemorrhage, Focal                    |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                              2                           |      1  2.0|
      Peribronchial, Inflammation, Chronic |       2                                            1                     |      5  1.6|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Degeneration, Hyaline                |                                           2                              |      7  2.0|
      Inflammation, Chronic, Focal         |       2                                   2        2                     |     10  2.0|
      Inflammation, Chronic                |    2     2  2  2  2     2  2  2  2  2  2     2  2     2  2               |     51  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  32                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 4| 4| 7| 4| 7| 7| 7| 7| 2| 7| 7| 2| 7| 7|              |            |
                             DAY ON TEST   | 5| 4| 8| 4| 4| 4| 5| 5| 4| 5| 4| 4| 4| 4| 8| 4| 4| 8| 4| 4|              |            |
                                           | 5| 2| 1| 2| 2| 2| 5| 6| 3| 6| 3| 2| 2| 2| 1| 3| 3| 0| 2| 2|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|              |      A     |
    250 PPM                                | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                              +  +                        |   2        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |             +                                                            |   4        |
      Hyperplasia                          |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Congestion                           |                                                                          |      1  2.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
      Infarct                              |                                  2                                       |      2  2.5|
      Inflammation, Chronic, Focal         |       2                                                                  |      1  2.0|
      Nephropathy                          |                                                                          |      1  2.0|
      Renal Tubule, Degeneration, Granular |                                                                          |      2  4.0|
      Renal Tubule, Regeneration           |                         1                                                |      3  1.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Inflammation, Chronic, Focal         |                      2                                                   |      9  1.6|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  33                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 2| 4| 6| 4| 7| 7| 7| 7| 7| 7| 4| 7| 6| 7| 4| 2| 7| 7| 7| 2| 6| 7|             
                             DAY ON TEST   | 4| 4| 4| 8| 5| 7| 5| 4| 4| 4| 4| 4| 4| 5| 4| 9| 4| 5| 8| 4| 4| 4| 8| 4| 4|             
                                           | 1| 2| 2| 0| 6| 7| 5| 2| 2| 2| 2| 2| 1| 6| 1| 5| 1| 6| 1| 1| 1| 1| 1| 8| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Dilatation                           |                                              4                           |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                | 2     3        2     2  2           3                          3         |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                                              X                           |             
      Eosinophilic Focus                   |       X              X  X  X                    X        X     X     X   |             
      Fatty Change                         |          1        1                                                      |             
      Necrosis, Focal                      | 1           1           1        2  1  1  2  4                       2   |             
                                            __________________________________________________________________________|             
   Mesentery                               |                      +                                   +               |             
      Fat, Necrosis                        |                      3                                   3               |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
      Acinus, Atrophy                      | 4                                                                        |             
      Duct, Ectasia                        | 4                                                                        |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                    2  1                  |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Subacute               |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Angiectasis                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                      4   |             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                2  1                          2        1                  |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  M  +  +  +  +  +  M  +  +  M  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
      Pars Distalis, Angiectasis           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  34                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 2| 4| 6| 4| 7| 7| 7| 7| 7| 7| 4| 7| 6| 7| 4| 2| 7| 7| 7| 2| 6| 7|             
                             DAY ON TEST   | 4| 4| 4| 8| 5| 7| 5| 4| 4| 4| 4| 4| 4| 5| 4| 9| 4| 5| 8| 4| 4| 4| 8| 4| 4|             
                                           | 1| 2| 2| 0| 6| 7| 5| 2| 2| 2| 2| 2| 1| 6| 1| 5| 1| 6| 1| 1| 1| 1| 1| 8| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |                                        1                    2            |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute, Focal           |                                                                          |             
      Follicle, Cyst                       |                                                                          |             
      Follicular Cell, Hyperplasia, Focal  |    1                                                     4  1            |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +        M     +  +  +  +  +  +     +  +  +        +  +  +     +  +|             
      Angiectasis                          |                               3                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | X                             X                 X                       X|             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          | 3                                                                        |             
      Fibrosis, Focal                      |                2                                                         |             
      Hydrometra                           |                            4     4     2     4  3  2                     |             
      Inflammation, Suppurative            |                            4                 4                           |             
      Thrombosis                           |                                                                          |             
      Endometrium, Hyperplasia, Cystic     | 1  2  1  3  2  2     3  1  1  3     4  1  3  1  2  1  2  2  3  2  1     3|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                              4                           |             
      Hyperplasia, Neutrophil              |                                                                      4   |             
      Myelofibrosis                        |                1                 1  3     1     2              2         |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                          +              +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphatic, Angiectasis               |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Lymphatic, Angiectasis               |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           | 2                             2                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                         3                    4           4  3        4   |             
      Hyperplasia, Lymphoid                |                                                 2              3         |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +|             
      Lactation                            |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  35                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 2| 4| 6| 4| 7| 7| 7| 7| 7| 7| 4| 7| 6| 7| 4| 2| 7| 7| 7| 2| 6| 7|             
                             DAY ON TEST   | 4| 4| 4| 8| 5| 7| 5| 4| 4| 4| 4| 4| 4| 5| 4| 9| 4| 5| 8| 4| 4| 4| 8| 4| 4|             
                                           | 1| 2| 2| 0| 6| 7| 5| 2| 2| 2| 2| 2| 1| 6| 1| 5| 1| 6| 1| 1| 1| 1| 1| 8| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |                                                                          |             
      Mineralization                       |    2  2              1  2     2  2        1  2  2  2     1     1         |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                1                                               1         |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |          2                                            2           2      |             
      Inflammation, Chronic, Focal         |          2                                            2           2      |             
      Inflammation, Chronic                | 2     2     2  2  2  2  2  2  2  2  2     2  1  2  2     2  2  2     2  2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                +        +                                                |             
      Hyperplasia                          |                         4                                                |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Glomerulosclerosis                   |                                                                          |             
      Infarct                              |                                           4              2               |             
      Mineralization                       |                                              1                           |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Regeneration           |                      2           2                                       |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |             1                                                     3      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  36                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 2| 7| 7| 4| 7| 7| 6| 7| 2| 4| 7| 4| 7| 2| 4| 2| 7| 7| 7| 4| 7| 2| 7|             
                             DAY ON TEST   | 5| 4| 8| 4| 4| 5| 4| 4| 9| 4| 8| 5| 4| 5| 4| 8| 5| 8| 4| 4| 4| 5| 4| 8| 4|             
                                           | 5| 1| 1| 1| 2| 5| 1| 1| 0| 1| 0| 5| 1| 6| 1| 1| 6| 0| 1| 1| 1| 6| 1| 0| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |    3     2                          2                                    |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                                                                          |             
      Eosinophilic Focus                   |    X     X  X  X  X  X     X                       X        X     X      |             
      Fatty Change                         |    1                       2                                   1         |             
      Necrosis, Focal                      |             3  1                          2                              |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                               2                                          |             
      Acinus, Atrophy                      |                                                                          |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         | 1              1                 2     2     1     2                 4   |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Subacute               |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |    +                                                                     |             
      Angiectasis                          |    3                                                                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        1                             2   |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  M  +  M  M  +  M  M  M  +  M  +  +  M  +  +  +  +  +  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                         2|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  37                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 2| 7| 7| 4| 7| 7| 6| 7| 2| 4| 7| 4| 7| 2| 4| 2| 7| 7| 7| 4| 7| 2| 7|             
                             DAY ON TEST   | 5| 4| 8| 4| 4| 5| 4| 4| 9| 4| 8| 5| 4| 5| 4| 8| 5| 8| 4| 4| 4| 5| 4| 8| 4|             
                                           | 5| 1| 1| 1| 2| 5| 1| 1| 0| 1| 0| 5| 1| 6| 1| 1| 6| 0| 1| 1| 1| 6| 1| 0| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |                            2              2              2               |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute, Focal           |                                     1                                    |             
      Follicle, Cyst                       |                                                          X               |             
      Follicular Cell, Hyperplasia, Focal  |                   1                                                      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |    +     +  +     +  +  +  +        +     +           M  +  +     +     +|             
      Angiectasis                          |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                X     X              X                                    |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Fibrosis, Focal                      |                                                                          |             
      Hydrometra                           |          4                 3     2                                       |             
      Inflammation, Suppurative            |                                                                          |             
      Thrombosis                           |                         X                                                |             
      Endometrium, Hyperplasia, Cystic     | 1  2  1  2  1  2  2  4  2  2  3  2  3  1  4  2     2  3  1  4  1  3     3|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia, Neutrophil              |                                                                          |             
      Myelofibrosis                        |    1        2  1                          1           1     1           2|             
                                            __________________________________________________________________________|             
   Lymph Node                              |                         +                                +               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Lymphatic, Angiectasis               |                                                          4               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphatic, Angiectasis               |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                     1                                    |             
      Hematopoietic Cell Proliferation     |                   4  3                                                   |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia, Lymphoid                |                                                          2               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lactation                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  38                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 2| 7| 7| 4| 7| 7| 6| 7| 2| 4| 7| 4| 7| 2| 4| 2| 7| 7| 7| 4| 7| 2| 7|             
                             DAY ON TEST   | 5| 4| 8| 4| 4| 5| 4| 4| 9| 4| 8| 5| 4| 5| 4| 8| 5| 8| 4| 4| 4| 5| 4| 8| 4|             
                                           | 5| 1| 1| 1| 2| 5| 1| 1| 0| 1| 0| 5| 1| 6| 1| 1| 6| 0| 1| 1| 1| 6| 1| 0| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    500 PPM                                | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |                                                                      1   |             
      Mineralization                       |                1     2  1  3     1  2  1  2     1        3  2  2  2     2|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |          1                                1                              |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |       2                       2                    2                     |             
      Inflammation, Chronic, Focal         |       2                       2              2     2                 2   |             
      Inflammation, Chronic                | 2  2     2  2  2  2  2  2  2     2  2  2  2     2     2  2  2  2  2     2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                     +                                    |             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Glomerulosclerosis                   |                                                                          |             
      Infarct                              |                                                       2                  |             
      Mineralization                       |                                                                          |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Regeneration           |             1                                                            |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         | 1              2              1        2     2  2                        |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  39                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 2|              |            |
                             DAY ON TEST   | 4| 6| 4| 4| 6| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 3| 8| 8|              |            |
                                           | 1| 0| 1| 1| 0| 1| 2| 1| 1| 1| 1| 1| 1| 2| 1| 1| 1| 9| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|              |      A     |
    500 PPM                                | 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +               |  68        |
      Dilatation                           |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia, Lymphoid                | 3  2  2        4        1                 2  3                           |     17  2.4|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia, Lymphoid                |                                        3                                 |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Basophilic Focus                     |                                                                          |      1     |
      Eosinophilic Focus                   | X        X     X  X        X        X  X     X  X                        |     27     |
      Fatty Change                         |                                                                          |      5  1.2|
      Necrosis, Focal                      |                                     2                                    |     13  1.8|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Fat, Necrosis                        |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                                                                          |      1  2.0|
      Acinus, Atrophy                      |                                              3                           |      2  3.5|
      Duct, Ectasia                        |                                              3                           |      2  3.5|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Inflammation, Chronic, Focal         |                                                                          |      9  1.8|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Subacute               |                3                                                         |      1  3.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Angiectasis                          |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Fibrosis                             |                                              1                           |      1  1.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  4.0|
      Hyperplasia, Focal                   |                                     2                                    |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  40                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 2|              |            |
                             DAY ON TEST   | 4| 6| 4| 4| 6| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 3| 8| 8|              |            |
                                           | 1| 0| 1| 1| 0| 1| 2| 1| 1| 1| 1| 1| 1| 2| 1| 1| 1| 9| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|              |      A     |
    500 PPM                                | 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia                          |       2        2           4           3                 1               |     11  1.9|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  M  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  51        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Pars Distalis, Angiectasis           |                                                                          |      1  2.0|
      Pars Distalis, Hyperplasia, Focal    | 2        2              3           2     3        2                     |     11  2.1|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Inflammation, Acute, Focal           |                                                                          |      1  1.0|
      Follicle, Cyst                       |                                                                          |      1     |
      Follicular Cell, Hyperplasia, Focal  |                            3                                             |      5  2.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +                     |  46        |
      Angiectasis                          |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Cyst                                 |                X     X                                                   |      9     |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |          2                                                               |      2  2.5|
      Fibrosis, Focal                      |                                                                          |      1  2.0|
      Hydrometra                           | 3  2        4                 4     4                                    |     14  3.2|
      Inflammation, Suppurative            |                                                                          |      2  4.0|
      Thrombosis                           |                                                                          |      1     |
      Endometrium, Hyperplasia, Cystic     | 2        2     3  3  3  3  4  1  2     1  3  4  3  3  2  2               |     61  2.2|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |                                                                          |      1  4.0|
      Hyperplasia, Neutrophil              |             3                                                            |      2  3.5|
      Myelofibrosis                        |                   2           2  1  3     3  2  1  4                     |     21  1.8|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                              +                           |   5        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Lymphatic, Angiectasis               |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +               |  67        |
      Lymphatic, Angiectasis               |                               4                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Congestion                           |                                                                          |      2  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  41                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 2|              |            |
                             DAY ON TEST   | 4| 6| 4| 4| 6| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 3| 8| 8|              |            |
                                           | 1| 0| 1| 1| 0| 1| 2| 1| 1| 1| 1| 1| 1| 2| 1| 1| 1| 9| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|              |      A     |
    500 PPM                                | 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Depletion Lymphoid                   |                                                                          |      1  1.0|
      Hematopoietic Cell Proliferation     |             4                          4                                 |      9  3.7|
      Hyperplasia, Lymphoid                |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Angiectasis                          |                            3                                             |      1  3.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  M  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Lactation                            |       X                                                                  |      2     |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic                |                                                    3                     |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Mineralization, Focal                |                                                                          |      1  1.0|
      Mineralization                       | 2  1     2  1  2  2  2  1  1        2  2        1                        |     38  1.7|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Alveolar Epithelium, Hyperplasia     |                                                                          |      4  1.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Degeneration, Hyaline                |                                                       2  2               |      8  2.0|
      Inflammation, Chronic, Focal         |                                                       2  2               |     10  2.0|
      Inflammation, Chronic                | 2  2  2  2  2  2  2     2     2  2  2  2  2  2  2  2                     |     56  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                +                       +                                 |   5        |
      Hyperplasia                          |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Glomerulosclerosis                   |    1                                                                     |      1  1.0|
      Infarct                              |                                                                          |      3  2.7|
      Mineralization                       |                                                                          |      1  1.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  42                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 2|              |            |
                             DAY ON TEST   | 4| 6| 4| 4| 6| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 3| 8| 8|              |            |
                                           | 1| 0| 1| 1| 0| 1| 2| 1| 1| 1| 1| 1| 1| 2| 1| 1| 1| 9| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|              |      A     |
    500 PPM                                | 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|              |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|              |            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Nephropathy                          |                                        2                                 |      1  2.0|
      Renal Tubule, Regeneration           |                                                                          |      3  1.7|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                                                       2                  |      9  1.8|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  43                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 7| 4| 6| 2| 7| 6| 4| 4| 4| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 4| 4| 5| 4| 5| 3| 7| 4| 7| 5| 5| 5| 4| 4| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 1| 1| 4| 1| 5| 9| 4| 1| 9| 4| 5| 5| 1| 1| 7| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +|             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                | 2  2        3     3     2  2           3  3     2  2     2              3|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |    1                                                        1            |             
      Basophilic Focus                     |                                                                          |             
      Clear Cell Focus                     |                                                                         X|             
      Eosinophilic Focus                   |    X                                      X                             X|             
      Fatty Change, Focal                  |                                                                          |             
      Fatty Change                         |    1           2        1                                   2            |             
      Necrosis, Focal                      |                         1                    1                           |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +                                                                     |             
      Hemorrhage, Focal                    |    2                                                                     |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                                                                2         |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                       +                  |             
      Hemorrhage, Focal                    |                                                                          |             
      Pigmentation, Focal                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ventricle, Hypertrophy               |                                                             3            |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  44                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 7| 4| 6| 2| 7| 6| 4| 4| 4| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 4| 4| 5| 4| 5| 3| 7| 4| 7| 5| 5| 5| 4| 4| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 1| 1| 4| 1| 5| 9| 4| 1| 9| 4| 5| 5| 1| 1| 7| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Focal                   | 2                                      2           3              1  1   |             
      Capsule, Hyperplasia                 |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                1           2  1              2              1            |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  M  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Cyst                  |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicle, Cyst                       |                                                                          |             
      Follicular Cell, Hyperplasia         |                                                    1                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Inflammation, Chronic                |                                                                         2|             
      Spermatocele                         |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +     +     +     +  +           +  +  +  +  +  +  +  +  +  +  +  +|             
      Abscess                              |                                                                          |             
      Cyst                                 | X  X        X     X        X           X  X     X  X  X  X  X  X  X  X  X|             
      Dilatation                           |       3                 3                    2  3  4     3  4            |             
      Hemorrhage, Focal                    |                                                                          |             
      Inflammation, Acute                  |             3              3                                             |             
      Inflammation, Chronic                |             3              3                       4  4        3         |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |    3                                                                     |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   | +  +  +     +           +              +  +     +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Myelofibrosis                        |                                                             2            |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +              +                                                      |             
      Pancreatic, Hyperplasia              |    4              2                                                      |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hyperplasia                          |                   2                                                      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  45                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 7| 4| 6| 2| 7| 6| 4| 4| 4| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 4| 4| 5| 4| 5| 3| 7| 4| 7| 5| 5| 5| 4| 4| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 1| 1| 4| 1| 5| 9| 4| 1| 9| 4| 5| 5| 1| 1| 7| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                                                      1   |             
      Fibrosis, Focal                      |                                                                   2      |             
      Hematopoietic Cell Proliferation     |                   3                                                      |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  I  +  +  +  +  +  +  +  M  +  +  +|             
      Cyst                                 |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |                      2                                                   |             
      Mineralization                       |    3                       2  2  1  2  1     2  2     2  2  3     2  2  3|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                 2                        |             
      Hemorrhage, Focal                    |                         2                       2                 2      |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Peribronchial, Inflammation, Chronic |                      1                                                   |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                      2                                                   |             
      Inflammation, Chronic                | 2     2  2  2     2     2  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                       +                  |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                            4                                             |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infarct                              |                                                                          |             
      Mineralization                       | 1     1  1              1                                1     3         |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Degeneration, Granular |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  46                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 7| 4| 6| 2| 7| 6| 4| 4| 4| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 4| 4| 5| 4| 5| 3| 7| 4| 7| 5| 5| 5| 4| 4| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
                                           | 1| 1| 1| 4| 1| 5| 9| 4| 1| 9| 4| 5| 5| 1| 1| 7| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Renal Tubule, Regeneration           | 1  2  1     1                 2        2  1           1        2  2     1|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  47                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 2| 7| 4| 2| 7| 7| 2| 4| 7| 4| 7| 7| 7| 2| 7| 7| 7| 7| 2| 7| 7| 7| 4|             
                             DAY ON TEST   | 7| 4| 7| 4| 5| 7| 4| 4| 7| 5| 4| 5| 4| 4| 4| 7| 4| 4| 4| 4| 7| 4| 4| 4| 5|             
                                           | 5| 1| 5| 1| 5| 5| 1| 1| 5| 4| 1| 4| 1| 1| 1| 5| 1| 1| 1| 1| 4| 1| 1| 1| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Ulcer                                |                                     3                                    |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |          3        4  3              3  2  2     2  2  3        4  3  2   |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                               4                                          |             
      Inflammation, Acute                  |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                   1                                   3                  |             
      Basophilic Focus                     |                                                                          |             
      Clear Cell Focus                     |          X        X                                                      |             
      Eosinophilic Focus                   |    X     X                                         X                     |             
      Fatty Change, Focal                  |                                                          1               |             
      Fatty Change                         |          2           2  2                                   3            |             
      Necrosis, Focal                      |                                                    3                     |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                  2                                       |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                           3                              |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                                        2                                 |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Pigmentation, Focal                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ventricle, Hypertrophy               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  48                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 2| 7| 4| 2| 7| 7| 2| 4| 7| 4| 7| 7| 7| 2| 7| 7| 7| 7| 2| 7| 7| 7| 4|             
                             DAY ON TEST   | 7| 4| 7| 4| 5| 7| 4| 4| 7| 5| 4| 5| 4| 4| 4| 7| 4| 4| 4| 4| 7| 4| 4| 4| 5|             
                                           | 5| 1| 5| 1| 5| 5| 1| 1| 5| 4| 1| 4| 1| 1| 1| 5| 1| 1| 1| 1| 4| 1| 1| 1| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Focal                   |    2     2  1                          2                                 |             
      Capsule, Hyperplasia                 |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    2     2  1     4  2  2           2  1  2        4                 3   |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  I  M  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Pars Distalis, Cyst                  |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicle, Cyst                       |                                                                          |             
      Follicular Cell, Hyperplasia         |                               1                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Spermatocele                         |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +     +  +     +  +        +     +  +  +     +  +  +  +     +  +  +  +|             
      Abscess                              |                                                                          |             
      Cyst                                 |          X        X  X        X     X  X  X     X  X     X           X   |             
      Dilatation                           |    3        3     3  3              3  3  4        4  3        4  4     3|             
      Hemorrhage, Focal                    |                      2                                                   |             
      Inflammation, Acute                  |                   4           4     4                                    |             
      Inflammation, Chronic                |                                                                      2   |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                      2   |             
      Dilatation                           |    2              4                             4                        |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |    +                                                                     |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Myelofibrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Pancreatic, Hyperplasia              |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Congestion                           |                               2                          2               |             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  49                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 2| 7| 4| 2| 7| 7| 2| 4| 7| 4| 7| 7| 7| 2| 7| 7| 7| 7| 2| 7| 7| 7| 4|             
                             DAY ON TEST   | 7| 4| 7| 4| 5| 7| 4| 4| 7| 5| 4| 5| 4| 4| 4| 7| 4| 4| 4| 4| 7| 4| 4| 4| 5|             
                                           | 5| 1| 5| 1| 5| 5| 1| 1| 5| 4| 1| 4| 1| 1| 1| 5| 1| 1| 1| 1| 4| 1| 1| 1| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                      1                 1        1                        |             
      Fibrosis, Focal                      |    3                                                                     |             
      Hematopoietic Cell Proliferation     |                                     4              3                 3   |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  +|             
      Cyst                                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |                1        2                                   2            |             
      Mineralization                       |    3              3  2        2  2     3           3  1  2     2  3  2  2|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                                1         |             
      Peribronchial, Inflammation, Chronic |                1        1                    1                           |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         | 2     2        1        2                    2              2            |             
      Inflammation, Chronic                |    2        2     2  2     2  2     2  2  2     2  2  2  2     2  2  2  2|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                        +                                 |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                     3                                2   |             
      Infarct                              |          2                                                               |             
      Mineralization                       |          1  1     1           1        2        1              1         |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Degeneration, Granular |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  50                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 7| 2| 7| 4| 2| 7| 7| 2| 4| 7| 4| 7| 7| 7| 2| 7| 7| 7| 7| 2| 7| 7| 7| 4|             
                             DAY ON TEST   | 7| 4| 7| 4| 5| 7| 4| 4| 7| 5| 4| 5| 4| 4| 4| 7| 4| 4| 4| 4| 7| 4| 4| 4| 5|             
                                           | 5| 1| 5| 1| 5| 5| 1| 1| 5| 4| 1| 4| 1| 1| 1| 5| 1| 1| 1| 1| 4| 1| 1| 1| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Renal Tubule, Regeneration           |    1     2                 1  1  1     2  2  1  2     1  1     2  1     1|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                            1                                             |             
      Perivascular, Inflammation, Chronic  |    2                                                                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  51                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 2| 7| 7| 7| 6| 7| 7| 7| 7| 2| 7| 6| 7| 7| 2|              |            |
                             DAY ON TEST   | 4| 5| 4| 4| 4| 7| 4| 4| 4| 1| 4| 4| 4| 4| 7| 4| 4| 4| 4| 7|              |            |
                                           | 1| 4| 1| 1| 1| 4| 1| 1| 1| 7| 1| 1| 1| 1| 5| 1| 0| 1| 1| 4|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      A     |
    0 PPM                                  | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  64        |
      Ulcer                                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
      Hyperplasia, Lymphoid                |       3  3        3  2     2     2     1     2     3                     |     33  2.5|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
      Hyperplasia, Lymphoid                |                         4           4                                    |      3  4.0|
      Inflammation, Acute                  |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  66        |
      Hyperplasia, Lymphoid                |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |                                                                          |      4  1.5|
      Basophilic Focus                     |                                                       X                  |      1     |
      Clear Cell Focus                     |    X                             X                                       |      5     |
      Eosinophilic Focus                   |                                                                          |      6     |
      Fatty Change, Focal                  |                                  1                                       |      2  1.0|
      Fatty Change                         |                1                    2     1        2                     |     12  1.8|
      Necrosis, Focal                      |                                                                          |      3  1.7|
      Thrombosis                           |                                              X                           |      1     |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                +                                                         |   2        |
      Hemorrhage, Focal                    |                                                                          |      1  2.0|
      Fat, Necrosis                        |                2                                                         |      1  2.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |    1                                                                     |      2  1.5|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Foreign Body                         |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
      Inflammation, Acute                  |                   3                                                      |      1  3.0|
      Inflammation, Chronic                |                                                                          |      2  2.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |       +                                      +                           |   3        |
      Hemorrhage, Focal                    |                                              4                           |      1  4.0|
      Pigmentation, Focal                  |       2                                                                  |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  52                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 2| 7| 7| 7| 6| 7| 7| 7| 7| 2| 7| 6| 7| 7| 2|              |            |
                             DAY ON TEST   | 4| 5| 4| 4| 4| 7| 4| 4| 4| 1| 4| 4| 4| 4| 7| 4| 4| 4| 4| 7|              |            |
                                           | 1| 4| 1| 1| 1| 4| 1| 1| 1| 7| 1| 1| 1| 1| 5| 1| 0| 1| 1| 4|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      A     |
    0 PPM                                  | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
      Ventricle, Hypertrophy               |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
      Atrophy                              |                                  2        2                              |      2  2.0|
      Hyperplasia, Focal                   |             3     2     2           2  2                                 |     14  1.9|
      Capsule, Hyperplasia                 |          2                                                               |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia                          |                1        3        1  3  1  1  1        2                  |     25  2.0|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  M  M  +  +  +  +  +  M  +  M  +  +  +  +  +  M  M  +  +               |  52        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Pars Distalis, Cyst                  |             X                                                            |      1     |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Follicle, Cyst                       |                                     X                                    |      1     |
      Follicular Cell, Hyperplasia         |                                                                          |      2  1.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Atrophy                              |                                              2                           |      1  2.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Spermatocele                         |                                        3                                 |      1  3.0|
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +     +  +  +  +  +  +  +  +     +  +  +  +  +               |  54        |
      Abscess                              |                                                          4               |      1  4.0|
      Cyst                                 | X     X           X  X  X        X              X  X  X                  |     36     |
      Dilatation                           | 4  3     4  4              4  3     3  3     2                           |     28  3.3|
      Hemorrhage, Focal                    |                                                                          |      1  2.0|
      Inflammation, Acute                  |          4                                                               |      6  3.7|
      Inflammation, Chronic                |          4  3                       4                                    |      9  3.3|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Depletion Cellular                   |       1                    2                 2                           |      4  1.8|
      Dilatation                           |                         3                                                |      5  3.2|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hypospermia                          |                                              2                           |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  53                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 2| 7| 7| 7| 6| 7| 7| 7| 7| 2| 7| 6| 7| 7| 2|              |            |
                             DAY ON TEST   | 4| 5| 4| 4| 4| 7| 4| 4| 4| 1| 4| 4| 4| 4| 7| 4| 4| 4| 4| 7|              |            |
                                           | 1| 4| 1| 1| 1| 4| 1| 1| 1| 7| 1| 1| 1| 1| 5| 1| 0| 1| 1| 4|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      A     |
    0 PPM                                  | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Blood                                   |                                                                          |  17        |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Myelofibrosis                        |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                            +                                             |   3        |
      Pancreatic, Hyperplasia              |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M               |  66        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +               |  68        |
      Congestion                           |                                                                          |      2  2.0|
      Hyperplasia                          |                                                                          |      1  2.0|
      Thrombosis                           |                                              4                           |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Congestion                           |                                        2                                 |      1  2.0|
      Depletion Lymphoid                   |                                                 3                        |      5  1.4|
      Fibrosis, Focal                      |                                                                          |      2  2.5|
      Hematopoietic Cell Proliferation     |                      4                       4                           |      6  3.5|
                                            __________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  M  +  +  M  +  +  +  M  +  +  +  M  M  +  +  +               |  58        |
      Cyst                                 |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M               |            |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Mineralization, Focal                |                                                          2               |      5  1.8|
      Mineralization                       | 3     2  2  2              2        2  2     3        2                  |     36  2.2|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |                                                                          |      1  2.0|
      Hemorrhage, Focal                    |       2                                2                                 |      5  2.0|
      Alveolar Epithelium, Hyperplasia     | 2                       1                                                |      3  1.3|
      Peribronchial, Inflammation, Chronic |                                                                          |      4  1.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                2                 2        2              2               |     11  1.9|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  54                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 2| 7| 7| 7| 6| 7| 7| 7| 7| 2| 7| 6| 7| 7| 2|              |            |
                             DAY ON TEST   | 4| 5| 4| 4| 4| 7| 4| 4| 4| 1| 4| 4| 4| 4| 7| 4| 4| 4| 4| 7|              |            |
                                           | 1| 4| 1| 1| 1| 4| 1| 1| 1| 7| 1| 1| 1| 1| 5| 1| 0| 1| 1| 4|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      A     |
    0 PPM                                  | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Inflammation, Chronic                | 2  2  2  2  2     2  2  2  2  2  2  2  2     2  2     2                  |     55  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                               +  +     +                                 |   5        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Cyst                                 | X                                                                        |      1     |
      Glomerulosclerosis                   |                                                                          |      1  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      2  2.5|
      Infarct                              |                                                                          |      1  2.0|
      Mineralization                       |          1  2           2                                                |     16  1.3|
      Nephropathy                          |                                              2                           |      1  2.0|
      Renal Tubule, Degeneration, Granular |                            4                                             |      1  4.0|
      Renal Tubule, Regeneration           | 3  2  1  1  2  1        2     1  1  1              1  2  1               |     38  1.4|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
      Inflammation, Chronic, Focal         |                                                                          |      1  1.0|
      Perivascular, Inflammation, Chronic  |                                                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  55                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 2| 6| 4| 7| 7| 4| 6| 7| 7| 7| 7| 4| 7| 7| 7| 7| 4| 4| 2| 7| 7|             
                             DAY ON TEST   | 5| 4| 4| 4| 7| 2| 5| 4| 0| 5| 7| 4| 4| 4| 4| 5| 4| 4| 4| 4| 5| 5| 7| 4| 4|             
                                           | 5| 0| 0| 0| 5| 8| 5| 0| 7| 5| 4| 0| 0| 0| 0| 4| 0| 0| 0| 0| 5| 5| 5| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    50 PPM                                 | 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  A  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                      3  4        3  2  3  3        4     2           3   |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                 1                        |             
      Basophilic Focus                     |                                     X                                    |             
      Clear Cell Focus                     |                                                                          |             
      Eosinophilic Focus                   |                      X                    X     X                        |             
      Fatty Change                         | 3                 2                          2                           |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Necrosis, Focal                      |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                     +                                    |             
      Fat, Necrosis                        |                                     4                                    |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                            2                                      1      |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                               2                                          |             
      Inflammation, Chronic                |                                                                          |             
      Mucosa, Hyperplasia, Focal           |                                                                      3   |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   | 3     2              2  2                       2                    2   |             
      Capsule, Hyperplasia, Focal          |          3                                                               |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
      Hyperplasia                          |          3                                                               |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1                       2     2  3  3        2     2  3              2  4|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  M  M  M  +  +  +  M  M  +  M  +  +  +  +  +  +  +  I  +  +  +  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  56                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 2| 6| 4| 7| 7| 4| 6| 7| 7| 7| 7| 4| 7| 7| 7| 7| 4| 4| 2| 7| 7|             
                             DAY ON TEST   | 5| 4| 4| 4| 7| 2| 5| 4| 0| 5| 7| 4| 4| 4| 4| 5| 4| 4| 4| 4| 5| 5| 7| 4| 4|             
                                           | 5| 0| 0| 0| 5| 8| 5| 0| 7| 5| 4| 0| 0| 0| 0| 4| 0| 0| 0| 0| 5| 5| 5| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    50 PPM                                 | 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Spermatocele                         |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +  +  +     +     +  +     +  +  +  +  +     +  +  +  +     +     +  +|             
      Cyst                                 |    X  X              X  X     X  X  X  X  X     X  X  X        X     X  X|             
      Dilatation                           |       3        2     3        3  2                 4     3               |             
      Inflammation, Acute                  |    3                                4     4              4               |             
      Inflammation, Chronic                |          4              1     3                    1                    2|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                               3     2                                    |             
      Dilatation                           |                         3                                               4|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                               +                       +                  |             
      Mediastinal, Infiltration Cellular,  |                                                                          |             
           Plasma Cell                     |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  I  +  +  +  M  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  M  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                          2               |             
      Hyperplasia, Lymphoid                |                                                             2            |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Cyst                                 |                                                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                                     3              4                     |             
      Hyperplasia, Lymphoid                |                                                             3            |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                             2            |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  57                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 2| 6| 4| 7| 7| 4| 6| 7| 7| 7| 7| 4| 7| 7| 7| 7| 4| 4| 2| 7| 7|             
                             DAY ON TEST   | 5| 4| 4| 4| 7| 2| 5| 4| 0| 5| 7| 4| 4| 4| 4| 5| 4| 4| 4| 4| 5| 5| 7| 4| 4|             
                                           | 5| 0| 0| 0| 5| 8| 5| 0| 7| 5| 4| 0| 0| 0| 0| 4| 0| 0| 0| 0| 5| 5| 5| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    50 PPM                                 | 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |             2                                                            |             
      Mineralization                       | 2  3  3  2     2  2  2  3  2        3                 3  3  2  2     2  2|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Infiltration Cellular, Histiocyte    |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Peribronchial, Inflammation, Chronic |             1                                                            |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                   2      |             
      Inflammation, Chronic                | 2  2  2  2     2  2  2  2  2  2  2     2  2  2  2  2  2  2  2        2  2|             
      Metaplasia, Squamous                 |             2                                                            |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                    +                     |             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                                     2                                    |             
      Hemorrhage                           |                                                                          |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                   1      |             
      Mineralization                       |    2           3                 2        1           1  1           1  1|             
      Renal Tubule, Regeneration           | 2  2  3  2        1  2     1     2           1  2  2           1        2|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                                                          |             
      Inflammation, Chronic, Focal         |                            1                                             |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  58                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 2| 2| 2| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 2| 2|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 4| 4| 4| 5| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 0| 4| 5| 4| 7| 7|             
                                           | 4| 4| 4| 4| 4| 0| 0| 0| 5| 0| 0| 1| 1| 1| 1| 1| 1| 1| 0| 8| 0| 4| 0| 4| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    50 PPM                                 | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                   2              4     2        3           4            |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Ulcer                                |                                                                   3      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                                                                   X      |             
      Clear Cell Focus                     |                                                       X                  |             
      Eosinophilic Focus                   |                         X                                         X      |             
      Fatty Change                         |       2  2              2              2        1     2     2            |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Necrosis, Focal                      |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                            3                                      2      |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |       2  1              2                                                |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                                          |             
      Inflammation, Chronic                |                                                             2            |             
      Mucosa, Hyperplasia, Focal           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization                       |                                                          4               |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                         2           2        2     2                     |             
      Capsule, Hyperplasia, Focal          |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    1  2           3     3        1     2           3  2     3     3      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  M  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  59                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 2| 2| 2| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 2| 2|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 4| 4| 4| 5| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 0| 4| 5| 4| 7| 7|             
                                           | 4| 4| 4| 4| 4| 0| 0| 0| 5| 0| 0| 1| 1| 1| 1| 1| 1| 1| 0| 8| 0| 4| 0| 4| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    50 PPM                                 | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |                                                             2            |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Spermatocele                         |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |          +     +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
      Cyst                                 |          X     X  X  X     X  X  X     X  X  X  X  X  X           X      |             
      Dilatation                           |                   4        4        2  3              4  3  4  3  2      |             
      Inflammation, Acute                  |                                        4           4                     |             
      Inflammation, Chronic                |                                              2              4            |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
      Inflammation, Chronic                |                                                                1         |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |                                                 4                        |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                          4        2      |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                     +                                    |             
      Mediastinal, Infiltration Cellular,  |                                                                          |             
           Plasma Cell                     |                                     3                                    |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Congestion                           |                   4                                3                     |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                   3      |             
      Cyst                                 |                         X                                                |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                   4  2                                2           3      |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  60                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 2| 2| 2| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 2| 2|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 4| 4| 4| 5| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 0| 4| 5| 4| 7| 7|             
                                           | 4| 4| 4| 4| 4| 0| 0| 0| 5| 0| 0| 1| 1| 1| 1| 1| 1| 1| 0| 8| 0| 4| 0| 4| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    50 PPM                                 | 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                | 2                                                                    2   |             
      Mineralization                       |                2  3  2  2  2  2     2        1  2  2        1  1         |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                         2|             
      Hemorrhage, Focal                    |                                                                          |             
      Infiltration Cellular, Histiocyte    |                                     4                                    |             
      Inflammation, Chronic                |                                           3                              |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Peribronchial, Inflammation, Chronic | 1           1                                                           1|             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         | 2  2  1     2                                                        2  2|             
      Inflammation, Chronic                |                2  1  1  2  2  2  2     2     2  2  2  2     2  2  2      |             
      Metaplasia, Squamous                 |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                          +               |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                             +            |             
      Hyperplasia                          |                                                             4            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Hemorrhage                           |                                                                          |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic, Focal         |                      2                                                   |             
      Mineralization                       |                1                                   1                     |             
      Renal Tubule, Regeneration           |    1  1     1  2  3     2  2     2           2     2     1  1     2      |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                                       X                  |             
      Inflammation, Chronic, Focal         |    2  1                                                        1        1|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  61                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 4| 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 4| 4| 4| 4| 4| 5| 5| 2| 7| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|              |            |
                                           | 1| 1| 1| 1| 1| 4| 5| 0| 4| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      A     |
    50 PPM                                 | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia, Lymphoid                |    2     2                       2        2                              |     18  2.8|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Hyperplasia, Lymphoid                |       4                                                                  |      1  4.0|
      Ulcer                                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |             2                                                            |      2  1.5|
      Basophilic Focus                     |                                                                          |      2     |
      Clear Cell Focus                     |             X                                         X                  |      3     |
      Eosinophilic Focus                   | X        X                 X  X                                          |      9     |
      Fatty Change                         | 2                                      1              2                  |     13  1.9|
      Inflammation, Chronic, Focal         |                                  3                                       |      1  3.0|
      Necrosis, Focal                      | 2                                                                        |      1  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               | +     +                                                                  |   3        |
      Fat, Necrosis                        | 2                                                                        |      2  3.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia, Focal                   |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                   2                          3                           |      7  1.9|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Erosion                              |                                                                          |      1  2.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Mucosa, Hyperplasia, Focal           |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Mineralization                       |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia, Focal                   | 2  2     2           3     2     2  2           2                        |     18  2.1|
      Capsule, Hyperplasia, Focal          |                                                                          |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  62                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 4| 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 4| 4| 4| 4| 4| 5| 5| 2| 7| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|              |            |
                                           | 1| 1| 1| 1| 1| 4| 5| 0| 4| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      A     |
    50 PPM                                 | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Hyperplasia                          |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Hyperplasia                          |       3  3  2              3                 2        3  2               |     27  2.4|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  M  M  +  M  M  M  +  M  +  +  +  +  +  +  +  M  M               |  47        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Follicular Cell, Hyperplasia         |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Spermatocele                         |             X                                                            |      1     |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +        +     +  +  +  +  +  +  +  +  +  +  +               |  53        |
      Cyst                                 | X  X  X  X  X        X     X        X  X        X  X  X  X               |     42     |
      Dilatation                           |       2                       4  4        2  4  4  4  4  4               |     25  3.2|
      Inflammation, Acute                  |       3              3                                                   |      8  3.6|
      Inflammation, Chronic                |                                           3                              |      8  2.5|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Inflammation, Chronic                |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Depletion Cellular                   |                                                                          |      2  2.5|
      Dilatation                           |                      4                                4                  |      5  3.8|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hypospermia                          |                      3                                                   |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia, Neutrophil              |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                               +  +                                       |   5        |
      Mediastinal, Infiltration Cellular,  |                                                                          |            |
           Plasma Cell                     |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Congestion                           |                                                                          |      3  3.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  63                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 4| 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 4| 4| 4| 4| 4| 5| 5| 2| 7| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|              |            |
                                           | 1| 1| 1| 1| 1| 4| 5| 0| 4| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      A     |
    50 PPM                                 | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Congestion                           |                                                                          |      1  3.0|
      Cyst                                 |                                                                          |      1     |
      Depletion Lymphoid                   |                                              1        1  1               |      3  1.0|
      Hematopoietic Cell Proliferation     |       2                                                                  |      7  2.9|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  M  +               |  60        |
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  +  M  M  M  M  M  M  M  M  M  M  M  M               |   1        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperostosis                         |                                  X                                       |      1     |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Mineralization, Focal                |                                                                          |      3  2.0|
      Mineralization                       | 2  3  1  1  3  2     2     1  2  3     2     2        3  3               |     42  2.1|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Congestion                           |                                                                          |      1  2.0|
      Hemorrhage, Focal                    | 2                                                                        |      1  2.0|
      Infiltration Cellular, Histiocyte    |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Alveolar Epithelium, Hyperplasia     |                                                 1                        |      1  1.0|
      Peribronchial, Inflammation, Chronic |                                                                          |      4  1.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                         2                                                |      8  1.9|
      Inflammation, Chronic                | 2  2  2  2  2  2     2     2  2  2  2  2  2  1  3  2  2                  |     53  2.0|
      Metaplasia, Squamous                 |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   2        |
      Hyperplasia                          |                                                                          |      1  4.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  64                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 4| 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 4| 4| 4| 4| 4| 5| 5| 2| 7| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|              |            |
                                           | 1| 1| 1| 1| 1| 4| 5| 0| 4| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|              |      A     |
    50 PPM                                 | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Cyst                                 |                                                 X                        |      1     |
      Glomerulosclerosis                   |                                                                          |      1  2.0|
      Hemorrhage                           |                                              3                           |      1  3.0|
      Infarct                              |       4                    3                                             |      2  3.5|
      Inflammation, Chronic, Focal         |                                                                          |      2  1.5|
      Mineralization                       |    1                             1                    2  1               |     14  1.4|
      Renal Tubule, Regeneration           | 2  2     3  2        1     2        2  2  3     1  2                     |     37  1.8|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Calculus Micro Observation Only      |                                                                          |      1     |
      Inflammation, Chronic, Focal         |                1                                                         |      6  1.2|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  65                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 2| 2| 7| 7| 7| 2| 7| 4| 7| 7| 7| 7| 5| 2| 4| 2| 7| 7| 4| 7| 4| 4| 7|             
                             DAY ON TEST   | 3| 7| 7| 7| 3| 3| 3| 7| 3| 5| 3| 3| 3| 3| 8| 7| 5| 7| 3| 3| 5| 3| 5| 5| 3|             
                                           | 7| 4| 5| 4| 7| 7| 7| 4| 7| 5| 7| 7| 7| 7| 5| 5| 5| 4| 6| 7| 4| 6| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                   2              2  3                 3  2     3        3|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                               X                                          |             
      Clear Cell Focus                     |                                                          X           X   |             
      Eosinophilic Focus                   | X           X                                                            |             
      Fatty Change                         |    1     1                 2        2           1        1  2            |             
      Inflammation, Chronic, Focal         |                                                                2         |             
      Necrosis, Focal                      |                   1                    1                                 |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Cyst                                 |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |          1                 2                                             |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis, Focal                |                                           4                              |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Perivascular, Inflammation, Chronic  |                      1                                                   |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                +         |             
      Hyperkeratosis, Focal                |                                                                3         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                               2  2  2  2                 2               |             
      Capsule, Hyperplasia                 |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1                 1  1     1     1                       1               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  66                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 2| 2| 7| 7| 7| 2| 7| 4| 7| 7| 7| 7| 5| 2| 4| 2| 7| 7| 4| 7| 4| 4| 7|             
                             DAY ON TEST   | 3| 7| 7| 7| 3| 3| 3| 7| 3| 5| 3| 3| 3| 3| 8| 7| 5| 7| 3| 3| 5| 3| 5| 5| 3|             
                                           | 7| 4| 5| 4| 7| 7| 7| 4| 7| 5| 7| 7| 7| 7| 5| 5| 5| 4| 6| 7| 4| 6| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  +  M  +  +  +  +  +  M  +  +  +  M  +  M  +  M  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  M  +  M  +  +  +  M  +  +  M  +  +  +  +  M  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                           2                              |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +           +  +  +     +     M  +  +  +  +     +     +  +  +  +     +  +|             
      Abscess                              |                                                                          |             
      Atrophy                              |                                                             2            |             
      Cyst                                 | X           X  X  X     X        X  X  X  X              X     X     X  X|             
      Dilatation                           | 3           3     4              4              3     4  3              4|             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                         2        3     4                                 |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                         2                 3                              |             
      Inflammation, Chronic, Focal         |    1                                                                     |             
      Inflammation, Chronic                |                                                 1                 1      |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                   3     2                 3                              |             
      Dilatation                           |                               4     3                                    |             
      Fibrosis                             |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                           4                              |             
      Seminiferous Tubule, Atrophy         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                                          |             
      Myelofibrosis                        | 2                                                                        |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                         4                                                |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                         2                                                |             
      Depletion Lymphoid                   |             2  1                          2                              |             
      Hematopoietic Cell Proliferation     |                                        4              3                  |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  67                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 2| 2| 2| 7| 7| 7| 2| 7| 4| 7| 7| 7| 7| 5| 2| 4| 2| 7| 7| 4| 7| 4| 4| 7|             
                             DAY ON TEST   | 3| 7| 7| 7| 3| 3| 3| 7| 3| 5| 3| 3| 3| 3| 8| 7| 5| 7| 3| 3| 5| 3| 5| 5| 3|             
                                           | 7| 4| 5| 4| 7| 7| 7| 4| 7| 5| 7| 7| 7| 7| 5| 5| 5| 4| 6| 7| 4| 6| 4| 5| 6|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |          1           2                       1     1                     |             
      Mineralization                       |             2     3     1  2  2  2  2     3     2     2  2     2         |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                         2                                                |             
      Hemorrhage, Focal                    |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                     2                                    |             
      Peribronchial, Inflammation, Chronic |    1     2           1                       2     1                     |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                      2                       2                           |             
      Inflammation, Chronic, Focal         |    2  2  2           2                       2     2                     |             
      Inflammation, Chronic                | 2           2  2  2     2     2  2  2  2  2     2     2  2  2  2  2  2  2|             
      Metaplasia, Squamous                 |                                                                          |             
      Olfactory Epithelium, Hyperplasia    |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infarct                              |                                                                          |             
      Metaplasia, Osseous                  |                                                                         3|             
      Mineralization                       |                1                                      1  1     1        1|             
      Nephropathy                          |                                        2                                 |             
      Renal Tubule, Regeneration           |    1        2  1        1  1           3        1  1     2     2        3|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Concretion                           |                                                                2         |             
      Ectasia                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                 1                        |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  68                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 4| 7| 4| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 2| 7| 7| 4|             
                             DAY ON TEST   | 3| 4| 3| 3| 4| 4| 5| 3| 5| 4| 4| 4| 4| 4| 4| 5| 4| 4| 4| 4| 4| 7| 4| 4| 5|             
                                           | 6| 1| 6| 6| 0| 0| 4| 1| 4| 0| 0| 0| 0| 0| 0| 5| 0| 0| 0| 0| 0| 5| 0| 0| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                | 4        3                    3  3     2              3  3           3   |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                  4                                   1   |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                 2                        |             
      Basophilic Focus                     |       X                                                           X     X|             
      Clear Cell Focus                     |                                           X                              |             
      Eosinophilic Focus                   |                            X        X     X                              |             
      Fatty Change                         |                2                             3                           |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Necrosis, Focal                      |    3                                                                     |             
      Thrombosis                           |                X                                                         |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                       +                  |             
      Cyst                                 |                                                       X                  |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                   1                                            1         |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis, Focal                |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |    2                                                                     |             
      Inflammation, Chronic                |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Hyperkeratosis, Focal                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   | 3                                      2              2              2   |             
      Capsule, Hyperplasia                 |                                                             2            |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   | 2                                                                        |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Hyperplasia                          |    1        2  1                          2  1  1                 2      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  69                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 4| 7| 4| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 2| 7| 7| 4|             
                             DAY ON TEST   | 3| 4| 3| 3| 4| 4| 5| 3| 5| 4| 4| 4| 4| 4| 4| 5| 4| 4| 4| 4| 4| 7| 4| 4| 5|             
                                           | 6| 1| 6| 6| 0| 0| 4| 1| 4| 0| 0| 0| 0| 0| 0| 5| 0| 0| 0| 0| 0| 5| 0| 0| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  +  +  +  M  M  M  +  +  M  +  M  +  +  +  +  +  +  M  I  M  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +   |             
      Abscess                              |                         3                                                |             
      Atrophy                              |                                                                          |             
      Cyst                                 |          X  X  X     X     X  X  X  X  X  X  X  X  X  X     X  X  X  X   |             
      Dilatation                           | 3  1  3     4        2     2        2                 2           2      |             
      Inflammation, Acute                  |             4                 4           4     2                 4  4   |             
      Inflammation, Chronic                |          4                             2     2           2  3            |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |                                        4  4                              |             
      Fibrosis                             |    4                                                                     |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
      Seminiferous Tubule, Atrophy         |                                     3                                    |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                                          |             
      Myelofibrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                    +                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
      Congestion                           |       3  2                                                               |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |    3                                      4                          3   |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  M  M  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  70                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 4| 7| 4| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 2| 7| 7| 4|             
                             DAY ON TEST   | 3| 4| 3| 3| 4| 4| 5| 3| 5| 4| 4| 4| 4| 4| 4| 5| 4| 4| 4| 4| 4| 7| 4| 4| 5|             
                                           | 6| 1| 6| 6| 0| 0| 4| 1| 4| 0| 0| 0| 0| 0| 0| 5| 0| 0| 0| 0| 0| 5| 0| 0| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    250 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization, Focal                |                                                                          |             
      Mineralization                       |          3        2  2              3     1     2  2  3  2           1   |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |             1                                                            |             
      Peribronchial, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                2         |             
      Inflammation, Chronic                | 2  2  2  2  2  2  2     2  2  2  2  2  2        2  2  2  2  2     2     2|             
      Metaplasia, Squamous                 |                                                                          |             
      Olfactory Epithelium, Hyperplasia    |                      2                                                   |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                          X               |             
      Glomerulosclerosis                   |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                      3   |             
      Infarct                              |                                                          2               |             
      Metaplasia, Osseous                  |                                                                          |             
      Mineralization                       |          2  1  1           1              1     1                        |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Regeneration           |       2  1  1  1  1     1  1  2  1     1  2        1  3  2  1     2      |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Concretion                           |                                                                          |             
      Ectasia                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                         1|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  71                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 6| 2| 7| 6| 7| 2| 7| 7| 6| 7|              |            |
                             DAY ON TEST   | 5| 4| 7| 4| 4| 4| 4| 4| 4| 4| 0| 7| 4| 2| 4| 7| 1| 4| 1| 4|              |            |
                                           | 4| 0| 5| 0| 0| 0| 0| 0| 0| 0| 1| 4| 0| 6| 0| 4| 0| 0| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    250 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  A  +  +  M  +  +  +  +  M  +               |  64        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
      Hyperplasia, Lymphoid                |    3     3        3     3  4        2  2                 3               |     23  2.8|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  M               |  67        |
      Hyperplasia, Lymphoid                |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Angiectasis                          |                                                                          |      1  2.0|
      Basophilic Focus                     |                                                       X                  |      5     |
      Clear Cell Focus                     |                                                                          |      3     |
      Eosinophilic Focus                   |          X     X     X              X                                    |      9     |
      Fatty Change                         |    2           3     2              2                                    |     13  1.8|
      Inflammation, Chronic, Focal         |                                                                          |      1  2.0|
      Necrosis, Focal                      |                   1                                                      |      4  1.5|
      Thrombosis                           |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
      Cyst                                 |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                                                                          |      4  1.3|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperkeratosis, Focal                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Erosion                              |                                                 2                        |      2  2.0|
      Inflammation, Chronic                |                                     2                                    |      1  2.0|
      Perivascular, Inflammation, Chronic  |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Hyperkeratosis, Focal                |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia, Focal                   |    2        2  1  1                       2        2                     |     15  1.9|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  72                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 6| 2| 7| 6| 7| 2| 7| 7| 6| 7|              |            |
                             DAY ON TEST   | 5| 4| 7| 4| 4| 4| 4| 4| 4| 4| 0| 7| 4| 2| 4| 7| 1| 4| 1| 4|              |            |
                                           | 4| 0| 5| 0| 0| 0| 0| 0| 0| 0| 1| 4| 0| 6| 0| 4| 0| 0| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    250 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Capsule, Hyperplasia                 |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia, Focal                   |                                        2                                 |      2  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia                          |    1     2     2        1     3  1  4  2        2                        |     22  1.5|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  +  M  M               |  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +               |  69        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Atrophy                              |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Penis                                   |             +                                                            |   1        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         |    +     +  +  +  +  +  +  +  +     +  +  +     +  +  +  +               |  55        |
      Abscess                              |                                                                          |      1  3.0|
      Atrophy                              |                                                                          |      1  2.0|
      Cyst                                 |    X              X  X  X     X     X  X  X     X  X     X               |     42     |
      Dilatation                           |                3  4  2  4  4        4              4  3                  |     25  3.1|
      Inflammation, Acute                  |             4                                                            |      7  3.7|
      Inflammation, Chronic                |          4                                                               |      9  2.9|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  M  +  +  +  +               |  67        |
      Atrophy                              |                                                                          |      2  2.5|
      Inflammation, Chronic, Focal         |                                  1                                       |      2  1.0|
      Inflammation, Chronic                |                                                                          |      2  1.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Depletion Cellular                   |                                                                          |      3  2.7|
      Dilatation                           |             4  4                                3                        |      7  3.7|
      Fibrosis                             |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hypospermia                          |                                                                          |      1  4.0|
      Seminiferous Tubule, Atrophy         |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperplasia, Neutrophil              |             2                                                            |      1  2.0|
      Myelofibrosis                        |                                                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  73                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 6| 2| 7| 6| 7| 2| 7| 7| 6| 7|              |            |
                             DAY ON TEST   | 5| 4| 7| 4| 4| 4| 4| 4| 4| 4| 0| 7| 4| 2| 4| 7| 1| 4| 1| 4|              |            |
                                           | 4| 0| 5| 0| 0| 0| 0| 0| 0| 0| 1| 4| 0| 6| 0| 4| 0| 0| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    250 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  67        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  M  +               |  65        |
      Congestion                           |                                                                          |      3  3.0|
      Hyperplasia                          |          4                                                               |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Congestion                           |                                                                          |      1  2.0|
      Depletion Lymphoid                   |                                                 3                        |      4  2.0|
      Hematopoietic Cell Proliferation     |          3  4                          4              3                  |      9  3.4|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  M  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  M  M  +               |  58        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M               |            |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Ulcer                                |             4                                                            |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Mineralization, Focal                |                                                                          |      4  1.3|
      Mineralization                       | 2                 2  2  2     2     2  2  2     3  1  2  2               |     34  2.1|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Congestion                           |                                                                          |      1  2.0|
      Hemorrhage, Focal                    |                            3                                             |      1  3.0|
      Alveolar Epithelium, Hyperplasia     |                2  2                                                      |      4  1.8|
      Peribronchial, Inflammation, Chronic |       2                          1                                       |      7  1.4|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Degeneration, Hyaline                |                                  1                                       |      3  1.7|
      Inflammation, Chronic, Focal         |       2                          2           2                           |     10  2.0|
      Inflammation, Chronic                | 2  2     2  2  2     2  2  2  2     2     2     2  2     2               |     52  2.0|
      Metaplasia, Squamous                 |                                  2                                       |      1  2.0|
      Olfactory Epithelium, Hyperplasia    |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +               |  68        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  74                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 4| 7| 2| 7| 7| 7| 7| 7| 7| 7| 6| 2| 7| 6| 7| 2| 7| 7| 6| 7|              |            |
                             DAY ON TEST   | 5| 4| 7| 4| 4| 4| 4| 4| 4| 4| 0| 7| 4| 2| 4| 7| 1| 4| 1| 4|              |            |
                                           | 4| 0| 5| 0| 0| 0| 0| 0| 0| 0| 1| 4| 0| 6| 0| 4| 0| 0| 0| 0|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    250 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Cyst                                 |                                                                          |      1     |
      Glomerulosclerosis                   |          2                                                               |      1  2.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Infarct                              |                                                                          |      1  2.0|
      Metaplasia, Osseous                  |                                                                          |      1  3.0|
      Mineralization                       |    1                 1                                                   |     13  1.1|
      Nephropathy                          |                                        4                                 |      2  3.0|
      Renal Tubule, Regeneration           | 1  1     2  1  2  1  2  1  1        2     2        1     1               |     40  1.5|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
      Concretion                           |                                                                          |      1  2.0|
      Ectasia                              |             4                                                            |      1  4.0|
      Inflammation, Chronic, Focal         |                                                                          |      2  1.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  75                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 2| 7| 7| 7| 6| 7| 4| 6| 2| 4| 7| 7| 7| 7| 7| 7| 7| 2| 7| 4| 7| 4| 7|             
                             DAY ON TEST   | 7| 3| 7| 3| 3| 3| 8| 3| 5| 5| 7| 5| 3| 3| 3| 3| 3| 3| 3| 7| 3| 5| 3| 5| 3|             
                                           | 4| 0| 5| 0| 3| 0| 7| 6| 5| 4| 4| 4| 6| 6| 3| 3| 3| 3| 3| 5| 3| 4| 3| 5| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | A  +  +  +  +  +  A  +  +  A  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                | 3  3              2                    2     3     2        3     2     2|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Acute                  |                   3                                                      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  +  A  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                         X                                                |             
      Clear Cell Focus                     |          X                 X        X                                    |             
      Eosinophilic Focus                   |          X        X                          X                           |             
      Fatty Change, Focal                  |                                                 2                        |             
      Fatty Change                         |    1     2           2     3  3     3        2           1     1     2   |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Necrosis, Focal                      |             3                                                            |             
      Thrombosis                           |                   X                                                      |             
      Artery, Inflammation, Acute          |                   4                                                      |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Mineralization                       |                                                                          |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                  2                       2     1         |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |          3                                                               |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                                          |             
      Hyperplasia                          |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |             +                                                            |             
      Hemorrhage, Focal                    |                                                                          |             
      Pigmentation, Focal                  |             2                                                            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  76                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 2| 7| 7| 7| 6| 7| 4| 6| 2| 4| 7| 7| 7| 7| 7| 7| 7| 2| 7| 4| 7| 4| 7|             
                             DAY ON TEST   | 7| 3| 7| 3| 3| 3| 8| 3| 5| 5| 7| 5| 3| 3| 3| 3| 3| 3| 3| 7| 3| 5| 3| 5| 3|             
                                           | 4| 0| 5| 0| 3| 0| 7| 6| 5| 4| 4| 4| 6| 6| 3| 3| 3| 3| 3| 5| 3| 4| 3| 5| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Fibrosis                             |             2                                                            |             
      Hyperplasia, Focal                   |          2                          1                                    |             
      Capsule, Hyperplasia                 |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Hyperplasia                          |                               2     2        1        3     4  1         |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  M  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | I  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +     +  +  +  +  +     +        +  +  +  +  +  +  +     +     +     +|             
      Cyst                                 | X  X     X  X     X  X     X        X     X  X        X     X     X     X|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |             4  4                    4  3  4     4  3              4     4|             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
      Inflammation, Acute                  |          4           4                                                   |             
      Inflammation, Chronic                |                                              2              4            |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Inflammation, Acute                  |                         3                                                |             
      Inflammation, Chronic                |                                  1                                   1   |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |    3                                         3                           |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
      Interstitial Cell, Hyperplasia       |                                                       2                  |             
      Seminiferous Tubule, Atrophy         |                                                                   2      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |                      +              +  +  +  +  +  +                     |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                   3                                                      |             
      Myelofibrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |             +              +                                             |             
      Renal, Lymphatic, Angiectasis        |             2                                                            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  77                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 2| 7| 7| 7| 6| 7| 4| 6| 2| 4| 7| 7| 7| 7| 7| 7| 7| 2| 7| 4| 7| 4| 7|             
                             DAY ON TEST   | 7| 3| 7| 3| 3| 3| 8| 3| 5| 5| 7| 5| 3| 3| 3| 3| 3| 3| 3| 7| 3| 5| 3| 5| 3|             
                                           | 4| 0| 5| 0| 3| 0| 7| 6| 5| 4| 4| 4| 6| 6| 3| 3| 3| 3| 3| 5| 3| 4| 3| 5| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                 2                        |             
      Fibrosis                             |             2                                                            |             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                   4                       3        2                     |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  I  +  +  +  +  M  +  +  +  +  M  +  M  I  +  M  +  M  +  M  M  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Mineralization, Focal                |       2                                                                  |             
      Mineralization                       | 2        2     1  1  1  2        1  2  3  1     2     1     2  1     2   |             
                                            __________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |          1                                            2                  |             
      Peribronchial, Inflammation, Chronic |                                                          1               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                                                                          |             
      Inflammation, Chronic, Focal         |       2                       2                          2               |             
      Inflammation, Chronic                | 2  2     2  2  2  2  2  2        2  2  3     2  2  2  3     2     2  2  2|             
      Metaplasia, Squamous                 |       2                                                                  |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                           +                              |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  78                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 2| 7| 7| 7| 6| 7| 4| 6| 2| 4| 7| 7| 7| 7| 7| 7| 7| 2| 7| 4| 7| 4| 7|             
                             DAY ON TEST   | 7| 3| 7| 3| 3| 3| 8| 3| 5| 5| 7| 5| 3| 3| 3| 3| 3| 3| 3| 7| 3| 5| 3| 5| 3|             
                                           | 4| 0| 5| 0| 3| 0| 7| 6| 5| 4| 4| 4| 6| 6| 3| 3| 3| 3| 3| 5| 3| 4| 3| 5| 4|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Casts                                |                                                                          |             
      Cyst                                 |                                                       X                  |             
      Glomerulosclerosis                   |                                                       2                  |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Mineralization                       |    1     1     1                                1                 1      |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Degeneration, Granular |             3                                                            |             
      Renal Tubule, Regeneration           |          2     2     1           1  1  1     3  2  1        1     2  1  2|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                                                          |             
      Concretion                           |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  79                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 7| 7| 7| 6| 7| 7| 4| 7| 2| 7| 2| 7| 2| 4| 7| 4| 4| 7| 7| 2| 7| 7| 7|             
                             DAY ON TEST   | 7| 7| 3| 3| 3| 1| 3| 3| 5| 3| 7| 3| 7| 3| 7| 5| 3| 5| 5| 3| 3| 7| 3| 3| 3|             
                                           | 5| 5| 3| 6| 6| 8| 5| 5| 4| 6| 5| 6| 4| 5| 5| 4| 5| 5| 5| 3| 3| 5| 3| 3| 3|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |       3  3  3                    2                                4      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                                                                          |             
      Clear Cell Focus                     |       X     X                                                            |             
      Eosinophilic Focus                   |             X                    X              X                 X     X|             
      Fatty Change, Focal                  |                                                          2               |             
      Fatty Change                         |    1        2     2                             2  1                     |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Necrosis, Focal                      |                                                                          |             
      Thrombosis                           |                                                                          |             
      Artery, Inflammation, Acute          |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                   +                                                      |             
      Mineralization                       |                                                                          |             
      Fat, Necrosis                        |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                    2                     |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                         1     2     2        1        2                  |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                                          |             
      Hyperplasia                          |                                                                          |             
      Inflammation, Chronic                |                   2        2                          1                  |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                             +            |             
      Hemorrhage, Focal                    |                                                             3            |             
      Pigmentation, Focal                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic, Focal         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  80                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 7| 7| 7| 6| 7| 7| 4| 7| 2| 7| 2| 7| 2| 4| 7| 4| 4| 7| 7| 2| 7| 7| 7|             
                             DAY ON TEST   | 7| 7| 3| 3| 3| 1| 3| 3| 5| 3| 7| 3| 7| 3| 7| 5| 3| 5| 5| 3| 3| 7| 3| 3| 3|             
                                           | 5| 5| 3| 6| 6| 8| 5| 5| 4| 6| 5| 6| 4| 5| 5| 4| 5| 5| 5| 3| 3| 5| 3| 3| 3|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Fibrosis                             |                                                                          |             
      Hyperplasia, Focal                   |             2        2     2                    2                 1      |             
      Capsule, Hyperplasia                 |                   2                                                      |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  M|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Hyperplasia                          |          1  4  3  1  2           1              1                        |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  M  +  M  +  M  +  +  +  M  +  M  M  M  M  +  M  +  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         |       +  +  +  +  +  +  +  +     +     +        +  +     +  +  +  +  +  +|             
      Cyst                                 |                X  X  X  X                                X     X  X      |             
      Depletion Cellular                   |                                                                         2|             
      Dilatation                           |       4  4        2  4     3     4     3        4  3     3  2        4   |             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
      Inflammation, Acute                  |                            4                                      4      |             
      Inflammation, Chronic                |             3                                                            |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  M  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Dilatation                           |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hypospermia                          |                                                                          |             
      Interstitial Cell, Hyperplasia       |                                                                          |             
      Seminiferous Tubule, Atrophy         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Neutrophil              |                                                                          |             
      Myelofibrosis                        |          2                                                               |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Renal, Lymphatic, Angiectasis        |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +|             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  81                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 7| 7| 7| 6| 7| 7| 4| 7| 2| 7| 2| 7| 2| 4| 7| 4| 4| 7| 7| 2| 7| 7| 7|             
                             DAY ON TEST   | 7| 7| 3| 3| 3| 1| 3| 3| 5| 3| 7| 3| 7| 3| 7| 5| 3| 5| 5| 3| 3| 7| 3| 3| 3|             
                                           | 5| 5| 3| 6| 6| 8| 5| 5| 4| 6| 5| 6| 4| 5| 5| 4| 5| 5| 5| 3| 3| 5| 3| 3| 3|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Fibrosis                             |                                                                          |             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Lymphoid                   |                                                                          |             
      Hematopoietic Cell Proliferation     |          2     3  3                                                      |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infiltration Cellular, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                             4            |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Mineralization, Focal                | 1                                   1     1                    1         |             
      Mineralization                       |          2     2     2  2        2                                2  2   |             
                                            __________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                 2                        |             
      Alveolar Epithelium, Hyperplasia     |             2                                                            |             
      Peribronchial, Inflammation, Chronic | 2                             1                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                | 2                                                              2         |             
      Inflammation, Chronic, Focal         | 2  2                          2     2     2                    2         |             
      Inflammation, Chronic                |       2  2  2  2  2  3  2  2     2     2     2     2  2  2        2  2  2|             
      Metaplasia, Squamous                 |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  82                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 2| 2| 7| 7| 7| 6| 7| 7| 4| 7| 2| 7| 2| 7| 2| 4| 7| 4| 4| 7| 7| 2| 7| 7| 7|             
                             DAY ON TEST   | 7| 7| 3| 3| 3| 1| 3| 3| 5| 3| 7| 3| 7| 3| 7| 5| 3| 5| 5| 3| 3| 7| 3| 3| 3|             
                                           | 5| 5| 3| 6| 6| 8| 5| 5| 4| 6| 5| 6| 4| 5| 5| 4| 5| 5| 5| 3| 3| 5| 3| 3| 3|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Casts                                |                                                                          |             
      Cyst                                 |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic, Focal         |                                                                          |             
      Mineralization                       |             1     1  1                          1        1        1      |             
      Nephropathy                          |                                                                         2|             
      Renal Tubule, Degeneration, Granular |                                                                          |             
      Renal Tubule, Regeneration           |    1        2  1  1  2     2                       1     1  1        2  2|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                               X                                          |             
      Concretion                           |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  83                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 2| 7| 4| 7| 4| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 8| 3| 7| 3| 5| 3| 5| 3| 3| 4| 3| 3| 0| 3| 2| 3| 3| 3| 0| 3|              |            |
                                           | 4| 6| 5| 3| 5| 3| 4| 3| 4| 7| 4| 4| 0| 3| 6| 4| 4| 3| 7| 3|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    500 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  62        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  A  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  67        |
      Hyperplasia, Lymphoid                | 2        2     3     3        3     3  3        3  3     3               |     24  2.7|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  66        |
      Hyperplasia, Lymphoid                |                                  4                                       |      1  4.0|
      Inflammation, Acute                  |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  65        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Basophilic Focus                     |                                                                          |      1     |
      Clear Cell Focus                     |                                                 X                        |      6     |
      Eosinophilic Focus                   |    X           X     X  X        X           X                           |     14     |
      Fatty Change, Focal                  |                                                                          |      2  2.0|
      Fatty Change                         |       1  2  2  2  1  2  2        2                 2                     |     24  1.8|
      Inflammation, Chronic, Focal         |                            2                                             |      1  2.0|
      Necrosis, Focal                      | 1                       2     1  1                    4                  |      6  2.0|
      Thrombosis                           |                                                                          |      1     |
      Artery, Inflammation, Acute          |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                 +                        |   2        |
      Mineralization                       |                                                 4                        |      1  4.0|
      Fat, Necrosis                        |                                                 4                        |      1  4.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                                                                          |      8  1.6|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Ulcer                                |                            3                                             |      2  3.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Erosion                              | 2                                                     2                  |      2  2.0|
      Hyperplasia                          |                      3                                                   |      1  3.0|
      Inflammation, Chronic                |                                                                          |      3  1.7|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   2        |
      Hemorrhage, Focal                    |                                                                          |      1  3.0|
      Pigmentation, Focal                  |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  84                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 2| 7| 4| 7| 4| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 8| 3| 7| 3| 5| 3| 5| 3| 3| 4| 3| 3| 0| 3| 2| 3| 3| 3| 0| 3|              |            |
                                           | 4| 6| 5| 3| 5| 3| 4| 3| 4| 7| 4| 4| 0| 3| 6| 4| 4| 3| 7| 3|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    500 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic, Focal         |                            2                                             |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Fibrosis                             |                                                                          |      1  2.0|
      Hyperplasia, Focal                   |          2     2        2     2        2        1                        |     13  1.8|
      Capsule, Hyperplasia                 |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  66        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Atrophy                              |                3                                                         |      1  3.0|
      Hyperplasia                          | 3        1  2        2  4                    2        2                  |     20  2.1|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  M  +  +  M  M  +  +  +  M  +  +  +               |  49        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  54        |
      Cyst                                 | X  X     X     X  X  X  X     X  X  X  X  X     X  X                     |     35     |
      Depletion Cellular                   |                                                                          |      1  2.0|
      Dilatation                           |          4  3           4        4  4        3           4               |     28  3.6|
      Infiltration Cellular, Plasma Cell   |                            3                                             |      1  3.0|
      Inflammation, Acute                  |                                                                          |      4  4.0|
      Inflammation, Chronic                |                3                          4     4                        |      6  3.3|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Atrophy                              |                                           3                              |      1  3.0|
      Inflammation, Acute                  |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                                                          |      2  1.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Depletion Cellular                   | 2                                         4                              |      2  3.0|
      Dilatation                           |                                     3                                    |      3  3.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hypospermia                          |                                     2     2                              |      2  2.0|
      Interstitial Cell, Hyperplasia       |                                                                          |      1  2.0|
      Seminiferous Tubule, Atrophy         |                            2                                             |      2  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  85                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 2| 7| 4| 7| 4| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 8| 3| 7| 3| 5| 3| 5| 3| 3| 4| 3| 3| 0| 3| 2| 3| 3| 3| 0| 3|              |            |
                                           | 4| 6| 5| 3| 5| 3| 4| 3| 4| 7| 4| 4| 0| 3| 6| 4| 4| 3| 7| 3|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    500 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Blood                                   |                                                                          |   7        |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hyperplasia, Neutrophil              |                            4                    3                        |      3  3.3|
      Myelofibrosis                        |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   2        |
      Renal, Lymphatic, Angiectasis        |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  66        |
      Infiltration Cellular, Plasma Cell   |                            4                                             |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  65        |
      Congestion                           |                                                 2                        |      2  2.0|
      Fibrosis                             |                                                                          |      1  2.0|
      Infiltration Cellular, Plasma Cell   |                            4                                             |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Depletion Lymphoid                   |                                     2                                    |      1  2.0|
      Hematopoietic Cell Proliferation     |                   4                                   4                  |      8  3.1|
      Hyperplasia, Lymphoid                |                         3                                                |      1  3.0|
      Infiltration Cellular, Plasma Cell   |                            3                                             |      1  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  M  +  +  M  +  M  +  +  +  M  +               |  56        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  +  M  M  M  +  M  M  M  M  M  M               |   2        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hyperostosis                         |                            3                                             |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Compression                          |                            4                                             |      1  4.0|
      Hemorrhage, Focal                    |                            3                                             |      1  3.0|
      Mineralization, Focal                |                                                                          |      5  1.2|
      Mineralization                       |    1     3           2  2  2  3  2  1           2  1  2  3               |     34  1.8|
                                            __________________________________________________________________________|____________|
   Peripheral Nerve                        |                                     +                                    |   1        |
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                     +                                    |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  86                                                               
NTP Experiment-Test: 05150-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/23/97  
Route: DOSED FEED                                                                                                 Time: 11:53:50  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 2| 7| 4| 7| 4| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|              |            |
                             DAY ON TEST   | 8| 3| 7| 3| 5| 3| 5| 3| 3| 4| 3| 3| 0| 3| 2| 3| 3| 3| 0| 3|              |            |
                                           | 4| 6| 5| 3| 5| 3| 4| 3| 4| 7| 4| 4| 0| 3| 6| 4| 4| 3| 7| 3|              |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|              |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|              |      A     |
    500 PPM                                | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|              |      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|              |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      3  1.7|
      Peribronchial, Inflammation, Chronic |                                                                          |      3  1.3|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Degeneration, Hyaline                |                                                                          |      2  2.0|
      Inflammation, Chronic, Focal         |       2                                                                  |     10  2.0|
      Inflammation, Chronic                | 2  2     2     2     2  2  2     2  2  2  2  2  2  2  2  2               |     52  2.1|
      Metaplasia, Squamous                 |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                      +                                                   |   2        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Casts                                |                   X                                                      |      1     |
      Cyst                                 |                                        X     X                           |      3     |
      Glomerulosclerosis                   |                                                                          |      1  2.0|
      Infarct                              |                                           2                              |      1  2.0|
      Inflammation, Chronic, Focal         |                                              2                           |      1  2.0|
      Mineralization                       |    2     2     1     2     2     1                       2               |     18  1.3|
      Nephropathy                          |                                                                          |      1  2.0|
      Renal Tubule, Degeneration, Granular |                                                       4                  |      2  3.5|
      Renal Tubule, Regeneration           |    1     1  1  2  2  1     1  2        2     2  1  2                     |     36  1.5|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  67        |
      Calculus Micro Observation Only      |                                                                          |      1     |
      Concretion                           |                            3                                             |      1  3.0|
      Perivascular, Inflammation, Chronic  |                            2                                             |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  87                                                               
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