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TDMS Study 05150-02 Pathology Tables

NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97
Route: DOSED FEED                                                                                                 Time: 16:31:36




       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




































Note:  Animals arranged according to CID number

                                                              Page   1

NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Polyp Adenomatous                    |       X                                                                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                      X                                                   |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                        X                                 |             
      Hemangiosarcoma                      |                                                                          |             
      Hepatocellular Carcinoma             |                                                    X                     |             
      Hepatocellular Carcinoma, Multiple   |                                     X                                    |             
      Hepatocellular Adenoma               |       X                          X                                       |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                      X     X                                             |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                         +|             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                +                                                         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  M  +  M  M  +  +  M  +  +  M  M  M  M  +  +  M  +  +  M  +  +  M  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page   2                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |                                        X     X                           |             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |       M        +  +  +  +  +        +  +  +  +     +        +  M        +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +|             
      Cystadenoma                          |    X                                                                     |             
      Teratoma NOS                         |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Histiocytic Sarcoma                  |                         X                                                |             
      Leiomyoma                            |                                              X                           |             
      Polyp Stromal                        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              |                      +                                                   |             
      Iliac, Lymphoma Malignant Mixed      |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                      X                                                   |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Pancreatic, Lymphoma Malignant Mixed |                      X                                                   |             
      Renal, Lymphoma Malignant Mixed      |                      X                                                   |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                      X                                                   |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                        X                                 |             
      Lymphoma Malignant Mixed             |                      X     X                                             |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  M  M  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   3                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         | X                                                                        |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                        +                                 |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                      +                                                   |             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                         X                                                |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                      X     X                                             |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   4                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Polyp Adenomatous                    |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Lymphoma Malignant Mixed             |                                           X                              |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Hemangiosarcoma                      |                                                                X         |             
      Hepatocellular Carcinoma             |                                                    X                 X   |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |                                                    X                     |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
      Lymphoma Malignant Mixed             |                                                       X                  |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                   +      |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |    X                                                                     |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                        +           +                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  M  +  M  +  M  M  I  +  +  +  +  +  +  +  M  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page   5                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Pars Distalis, Adenoma               |    X                    X                    X                           |             
      Pars Intermedia, Adenoma             |             X                                                            |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                         +                                                |             
      Hemangiosarcoma                      |                         X                                                |             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |    +  +  +  +        +  +  +  +  +     M  +  +  +  M  M  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +|             
      Cystadenoma                          |                                                 X                        |             
      Teratoma NOS                         |          X                                                               |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                 X                        |             
      Leiomyoma                            |                                                                          |             
      Polyp Stromal                        |                            X                          X                  |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              |                         +     +                          +               |             
      Iliac, Lymphoma Malignant Mixed      |                                                          X               |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                          X               |             
      Pancreatic, Lymphoma Malignant Mixed |                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                          X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +|             
      Lymphoma Malignant Mixed             |                                           X              X              X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                         X                                                |             
      Lymphoma Malignant Mixed             |                                        X              X  X              X|             
                                            __________________________________________________________________________|             
   Thymus                                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                          X               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   6                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |    +                                                                     |             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                  X                                       |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                      X   |             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  A  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                 X                        |             
      Lymphoma Malignant Lymphocytic       |    X                                                                     |             
      Lymphoma Malignant Mixed             |                                        X  X           X  X              X|             
 _____________________________________________________________________________________________________________________|             
                                                             Page   7                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
      Lymphoma Malignant Mixed             |                                  X                                       |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Lymphoma Malignant Mixed             |                                  X                                       |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Polyp Adenomatous                    |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Lymphoma Malignant Mixed             |                                           X                              |          3 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Hemangioma                           |                                                                          |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |                                                                          |          3 |
      Hepatocellular Carcinoma, Multiple   |          X                                                               |          2 |
      Hepatocellular Adenoma               |                                     X        X                           |          5 |
      Hepatocellular Adenoma, Multiple     |          X                                            X                  |          2 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                  X        X                              |          5 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |          +                 +                    +     +                  |   6        |
      Sarcoma                              |          X                                                               |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                  X                                       |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +                  |  67        |
      Squamous Cell Papilloma              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   3        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page   8                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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                   |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant Mixed             |                                  X                                       |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Adenoma                              |    X                                                                     |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  +  M  M  M  M  +  +  M  M  +  +  +  +  +  +  +                  |  43        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Pars Distalis, Adenoma               |                            X                 X                           |          7 |
      Pars Intermedia, Adenoma             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |    +                                                                     |   2        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Lymphoma Malignant Mixed             |    X                                                                     |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |    +     +  +           +  +     +  +  +  +  +  +  +  +                  |  43        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Cystadenoma                          |                                                                          |          2 |
      Teratoma NOS                         |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Hemangioma                           |                                        X                                 |          1 |
      Histiocytic Sarcoma                  |                                                                          |          2 |
      Leiomyoma                            |                                                                          |          1 |
      Polyp Stromal                        |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                  +  +     +                              |   7        |
      Iliac, Lymphoma Malignant Mixed      |                                                                          |          1 |
      Lumbar, Lymphoma Malignant Mixed     |                                  X                                       |          2 |
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |          1 |
      Pancreatic, Lymphoma Malignant Mixed |                                                                          |          1 |
      Renal, Lymphoma Malignant Mixed      |                                           X                              |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Lymphoma Malignant Mixed             |    X                             X        X                              |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Lymphoma Malignant Mixed             |    X                             X        X                              |          7 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page   9                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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               |                                                                          |            |
                                           |                                                                          |            |
      Hemangiosarcoma                      |                                                                          |          2 |
      Lymphoma Malignant Mixed             |    X                    X        X        X                              |         10 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
      Lymphoma Malignant Mixed             |                                  X        X                              |          4 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  M  +  +  M  +  M  +  +  +  +  M  +  M  +  +  +                  |  59        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Lymphoma Malignant Mixed             |                                  X                                       |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          2 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |          X                                                               |          2 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                     +                                    |   2        |
      Adenoma                              |                                     X                                    |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Lymphoma Malignant Mixed             |                                  X        X                              |          3 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +                  |  63        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  69        |
      Histiocytic Sarcoma                  |                                                                          |          2 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  10                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|                 |            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |    X                    X        X        X                              |         11 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  11                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Adenocarcinoma                       |                                                                X         |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Hepatocellular Carcinoma             |                                                                          |             
      Hepatocellular Adenoma               | X                                            X                 X        X|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                              X     X                     |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +     +  I  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  +  +  +  +  +  +  +  +  +  M  M  M  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |       X                       X  X                       X               |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +     +  M     +  +           +  +  M  +     +     +     +  +  +  +      |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Cystadenoma                          | X                                                           X            |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  12                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Cystadenoma, Multiple                |                                              X                           |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Teratoma NOS                         |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                               +                    +                     |             
      Lumbar, Lymphoma Malignant           |                                                                          |             
          Lymphocytic                      |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                               X                                          |             
      Mediastinal, Lymphoma Malignant      |                                                                          |             
          Lymphocytic                      |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Pancreatic, Lymphoma Malignant Mixed |                                                                          |             
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                    X                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +     M  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                               X                    X                     |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                              X     X                     |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                               X                    X                     |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +     +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  13                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |          X                                                               |             
      Lymphoma Malignant Mixed             |                                                                          |             
      Osteosarcoma, Metastatic, Uncertain  |                                                                          |             
          Primary Site                     |                                                                   X      |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                  +                                       |             
      Carcinoma                            |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                               X              X     X                     |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                               X              X     X                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  14                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +|             
      Adenocarcinoma                       |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                    X                     |             
      Hepatocellular Carcinoma             |                         X                                                |             
      Hepatocellular Adenoma               |       X              X  X                    X                           |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                      X                                            X      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  M  +  M  +  +  M  +  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               | X        X  X           X                                                |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |       X                                      X                           |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +     M  +  +  +     +  +  +  +  +  +  +     +  +  M     +        +     +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                      X                                      X            |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  15                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Cystadenoma, Multiple                |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Teratoma NOS                         |                                           X                              |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |       +        +                                                         |             
      Lumbar, Lymphoma Malignant           |                                                                          |             
          Lymphocytic                      |                X                                                         |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Mediastinal, Lymphoma Malignant      |                                                                          |             
          Lymphocytic                      |                X                                                         |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Pancreatic, Lymphoma Malignant Mixed |       X                                                                  |             
      Renal, Lymphoma Malignant Lymphocytic|                X                                                         |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |       X  X                                                               |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |       X                                                                  |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                         X                                                |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  16                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                             +            |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
      Osteosarcoma, Metastatic, Uncertain  |                                                                          |             
          Primary Site                     |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |                            X                    X                        |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  A  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  A  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                X                                                         |             
      Lymphoma Malignant Mixed             |       X  X                 X                    X                        |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  17                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  63        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  62        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  63        |
      Adenocarcinoma                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  61        |
      Lymphoma Malignant Mixed             |                   X                                                      |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |                            X                          X                  |          3 |
      Hepatocellular Adenoma               |                         X  X                    X                        |         11 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +                  |  67        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Squamous Cell Papilloma              |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A  +                  |  65        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  64        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Adenoma                              |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  M  M  M  +  +  M  M  M  M  +  +  +  +  M  M  +                  |  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Pars Distalis, Adenoma               | X                    X                                                   |         10 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Follicular Cell, Adenoma             | X                          X  X                 X                        |          6 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  18                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|                 |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +           +     +  +  +  +  +     +        +  +  +  +                  |  41        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Cystadenoma                          |                                                                          |          4 |
      Cystadenoma, Multiple                |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Teratoma NOS                         |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             | X                                                                        |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +                 +                                +                     |   7        |
      Lumbar, Lymphoma Malignant           |                                                                          |            |
          Lymphocytic                      |                                                                          |          1 |
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |          1 |
      Mediastinal, Lymphoma Malignant      |                                                                          |            |
          Lymphocytic                      |                                                                          |          1 |
      Mediastinal, Lymphoma Malignant Mixed|                   X                                X                     |          2 |
      Pancreatic, Lymphoma Malignant Mixed | X                                                                        |          2 |
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |          1 |
      Renal, Lymphoma Malignant Mixed      | X                                                  X                     |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +                  |  61        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  66        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                   X     X     X                                          |          7 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             | X                 X     X                                                |          6 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  M                  |  66        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                   X     X                          X                     |          5 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M                  |  60        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  19                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|                 |            |
 __________________________________________________________________________________________________________________________________ 
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Sarcoma                              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                         X                                                |          1 |
      Osteosarcoma, Metastatic, Uncertain  |                                                                          |            |
          Primary Site                     |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                  +                                       |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   1        |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  67        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                         X                                                |          6 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  A  +  +  +  M  +  +  +  +  +  +  +  +  A  +                  |  59        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                  |  68        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             | X                 X     X     X                    X                     |         12 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  20                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                            X                                             |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Hepatocellular Carcinoma             |                                                                          |             
      Hepatocellular Adenoma               |                            X           X                    X            |             
      Hepatocellular Adenoma, Multiple     |                                     X     X                              |             
      Histiocytic Sarcoma                  |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                          X               |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Malignant           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  21                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                     X                                    |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |       X                             X              X  X           X      |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Carcinoma           |          X                                                               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +        +  +  +     +  +  +  M     +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Polyp Stromal                        |                                                             X  X         |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +  +  +                                                           +   |             
      Axillary, Lymphoma Malignant         |                                                                          |             
          Lymphocytic                      |                                                                      X   |             
      Iliac, Lymphoma Malignant Lymphocytic|                                                                      X   |             
      Inguinal, Lymphoma Malignant         |                                                                          |             
          Lymphocytic                      |                                                                      X   |             
      Lumbar, Histiocytic Sarcoma,         |                                                                          |             
          Metastatic, Uterus               |                                                                          |             
      Lumbar, Lymphoma Malignant           |                                                                          |             
          Lymphocytic                      |                                                                      X   |             
      Lumbar, Lymphoma Malignant Mixed     |    X                                                                     |             
      Lumbar, Sarcoma, Metastatic, Skin    |                                                                          |             
      Mediastinal, Lymphoma Malignant      |                                                                          |             
          Lymphocytic                      |                                                                      X   |             
      Mediastinal, Lymphoma Malignant Mixed|    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  22                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
      Renal, Lymphoma Malignant Lymphocytic|                                                                      X   |             
      Renal, Lymphoma Malignant Mixed      |    X                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                         X                                                |             
      Hemangiosarcoma                      |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M|             
      Adenocarcinoma                       |                                                                          |             
      Adenoma                              |       X                                                                  |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  23                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                           X           X                  |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
      Carcinoma, Metastatic, Thyroid Gland |          X                                                               |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Sarcoma, Metastatic, Skin            |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                  +                    +     +            |             
      Adenoma                              |                                  X                          X            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  A  +  +  +  +  +  +  +  +  +  +  +  M  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                      X   |             
      Lymphoma Malignant Mixed             |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  24                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                   X                                                      |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                         X|             
      Hepatocellular Carcinoma             |                                                    X                     |             
      Hepatocellular Adenoma               |       X        X                                   X                     |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
      Histiocytic Sarcoma                  |    X                                                                     |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Mesentery                               | +                                                                        |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                      X                                                   |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  M  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Malignant           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  25                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                              X                           |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  M  M  M  M  +  +  M  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |                                     X        X     X                     |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Carcinoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +     +     +  +  A  +        +     +  +     +           +  +  +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |    X                                                                     |             
      Histiocytic Sarcoma                  |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Polyp Stromal                        |                                     X        X                           |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  A  +  +  +  +  +  +  A  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                   X      |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |             +                             +                              |             
      Axillary, Lymphoma Malignant         |                                                                          |             
          Lymphocytic                      |                                                                          |             
      Iliac, Lymphoma Malignant Lymphocytic|                                                                          |             
      Inguinal, Lymphoma Malignant         |                                                                          |             
          Lymphocytic                      |                                                                          |             
      Lumbar, Histiocytic Sarcoma,         |                                                                          |             
          Metastatic, Uterus               |             X                                                            |             
      Lumbar, Lymphoma Malignant           |                                                                          |             
          Lymphocytic                      |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Lumbar, Sarcoma, Metastatic, Skin    |                                                                          |             
      Mediastinal, Lymphoma Malignant      |                                                                          |             
          Lymphocytic                      |                                           X                              |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  26                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |    X                                                                     |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  M  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |    X                                                                     |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Hemangiosarcoma                      |                                                                   X      |             
      Histiocytic Sarcoma                  |    X                                                                     |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                      X                                                   |             
      Histiocytic Sarcoma                  |    X                                                                     |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                           X                              |             
      Lymphoma Malignant Mixed             |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma                       |                                                                X         |             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                   X      |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  27                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                   X  X   |             
      Alveolar/Bronchiolar Carcinoma       |                      X                                                   |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                      X                                                   |             
      Carcinoma, Metastatic, Thyroid Gland |                                                                          |             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Sarcoma, Metastatic, Skin            |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma, Metastatic,     |                                                                          |             
           Uterus                          |             X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |    X        X                                                            |             
      Lymphoma Malignant Lymphocytic       |                                           X                              |             
      Lymphoma Malignant Mixed             |                   X                                                     X|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  28                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Hemangioma                           |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |                X                                                         |          2 |
      Hepatocellular Adenoma               |                                     X                    X               |          8 |
      Hepatocellular Adenoma, Multiple     |    X                                                                     |          3 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |                X                                                         |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Squamous Cell Papilloma              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  29                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  66        |
      Pheochromocytoma Malignant           |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenoma                              |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  +  M  +  +  +  M  +  +  M  +  +  M               |  53        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +               |  68        |
      Pars Distalis, Adenoma               |    X     X  X                    X  X           X     X                  |         15 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  68        |
      Follicular Cell, Carcinoma           |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |    +     +  M  +        +     +  M  +  +     +  +     +  +               |  44        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Cystadenoma                          |                               X                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemangioma                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Polyp Stromal                        |          X                             X                                 |          6 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                        +              +                  |   8        |
      Axillary, Lymphoma Malignant         |                                                                          |            |
          Lymphocytic                      |                                                                          |          1 |
      Iliac, Lymphoma Malignant Lymphocytic|                                                                          |          1 |
      Inguinal, Lymphoma Malignant         |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  30                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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               |                                                                          |            |
                                           |                                                                          |            |
          Lymphocytic                      |                                                                          |          1 |
      Lumbar, Histiocytic Sarcoma,         |                                                                          |            |
          Metastatic, Uterus               |                                                                          |          1 |
      Lumbar, Lymphoma Malignant           |                                                                          |            |
          Lymphocytic                      |                                                                          |          1 |
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |          1 |
      Lumbar, Sarcoma, Metastatic, Skin    |                                        X                                 |          1 |
      Mediastinal, Lymphoma Malignant      |                                                                          |            |
          Lymphocytic                      |                                                                          |          2 |
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |          1 |
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |          1 |
      Renal, Lymphoma Malignant Mixed      |                                                       X                  |          2 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                X                                                         |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                       X                  |          3 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Hemangioma                           |                                                                          |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                       X  X               |          4 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  67        |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          2 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  31                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +               |  63        |
      Adenocarcinoma                       |                                                                          |          1 |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Sarcoma                              |                                        X                                 |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          4 |
      Alveolar/Bronchiolar Carcinoma       |                                                          X               |          2 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                                                          |          1 |
      Carcinoma, Metastatic, Thyroid Gland |                                                                          |          1 |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Sarcoma, Metastatic, Skin            |                                        X                                 |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma, Metastatic,     |                                                                          |            |
           Uterus                          |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                              +  +                        |   2        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |             +                                                            |   4        |
      Adenoma                              |             X                                                            |          3 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  32                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                X                                                         |          2 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |                                                                          |          2 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          2 |
      Lymphoma Malignant Mixed             |                X                                      X  X               |          6 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  33                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |    X                                                                    X|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |                         X                                                |             
      Hepatocellular Carcinoma, Multiple   |                                                             X            |             
      Hepatocellular Adenoma               | X                       X           X                          X         |             
      Hepatocellular Adenoma, Multiple     |    X  X                    X     X        X              X  X            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                           X                              |             
                                            __________________________________________________________________________|             
   Mesentery                               |                      +                                   +               |             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |    X                                                                     |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
      Capsule, Adenoma                     |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                X         |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  M  +  +  +  +  +  M  +  +  M  M  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  34                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
      Pars Distalis, Adenoma               |    X                          X                    X     X     X         |             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                X     X                                   X               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +        M     +  +  +  +  +  +     +  +  +        +  +  +     +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                X                                                         |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Polyp Stromal                        |                                                                          |             
      Endometrium, Adenocarcinoma          |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                          +              +|             
      Lumbar, Lymphoma Malignant Mixed     |                                                          X               |             
      Mediastinal, Lymphoma Malignant Mixed|                                                          X              X|             
      Renal, Lymphoma Malignant Mixed      |                                                          X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                X                                                         |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X              X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |    X                                      X              X              X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |    X                                      X                             X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
      Lymphoma Malignant Lymphocytic       |                               X                                          |             
      Lymphoma Malignant Mixed             |                                                          X               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  35                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Sarcoma                              |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
      Alveolar/Bronchiolar Adenoma         |                      X                                                   |             
      Alveolar/Bronchiolar Carcinoma       |                                                                X         |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                X                                                         |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X              X|             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                X                                                         |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                +        +                                                |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                X                                                         |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                      X   |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  36                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS - cont                   |                                                                          |             
                                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                               X                                          |             
      Lymphoma Malignant Mixed             |    X                                      X              X              X|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  37                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                      X                                                   |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |                                                                          |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |             X     X     X           X                          X  X      |             
      Hepatocellular Adenoma, Multiple     |    X                       X                          X  X               |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                   X                                      X               |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |    +                                                                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
      Capsule, Adenoma                     |             X                                                            |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                             X            |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  M  +  M  M  +  M  M  M  +  M  +  +  M  +  +  +  +  +  +  +  M|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  38                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Pars Distalis, Adenoma               |             X           X                                                |             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |    +     +  +     +  +  +  +        +     +           M  +  +     +     +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                 X                        |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Polyp Stromal                        |                                                          X               |             
      Endometrium, Adenocarcinoma          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                         +                                +               |             
      Lumbar, Lymphoma Malignant Mixed     |                         X                                X               |             
      Mediastinal, Lymphoma Malignant Mixed|                         X                                                |             
      Renal, Lymphoma Malignant Mixed      |                         X                                                |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                         X                                                |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                         X                                                |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                         X                                                |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                   X     X                                                |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  39                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                             X            |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
      Alveolar/Bronchiolar Adenoma         |                   X     X                                   X            |             
      Alveolar/Bronchiolar Carcinoma       |                                                             X            |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                     +                                    |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  40                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS - cont                   |                                                                          |             
                                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                             X            |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                   X  X  X                                X               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  41                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                 X                        |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |       X                                      X                           |          4 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Lymphoma Malignant Mixed             |                               X                                          |          2 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hepatocellular Carcinoma             |             X  X                       X        X                        |          5 |
      Hepatocellular Carcinoma, Multiple   |                                                                          |          1 |
      Hepatocellular Adenoma               | X              X        X                 X                              |         14 |
      Hepatocellular Adenoma, Multiple     |       X           X                    X     X                           |         15 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |                               X              X                           |          5 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
      Capsule, Adenoma                     |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  42                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Pheochromocytoma Benign              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  M  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  51        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Pars Distalis, Adenoma               |       X                    X                                             |          9 |
      Pars Intermedia, Adenoma             |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Follicular Cell, Adenoma             |                            X                                             |          4 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +                     |  46        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
      Cystadenoma                          |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |       X                                                                  |          1 |
      Polyp Stromal                        |                                                                          |          1 |
      Endometrium, Adenocarcinoma          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                              +                           |   5        |
      Lumbar, Lymphoma Malignant Mixed     |                                              X                           |          4 |
      Mediastinal, Lymphoma Malignant Mixed|                                              X                           |          4 |
      Renal, Lymphoma Malignant Mixed      |                                              X                           |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |          X                                                               |          4 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +               |  67        |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  43                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant Mixed             |          X                    X              X                           |          8 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                      X                          X                        |          2 |
      Lymphoma Malignant Mixed             |          X     X              X           X  X                           |          9 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                          X                        |          3 |
      Lymphoma Malignant Mixed             |          X                                   X                           |          5 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  M  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Sarcoma                              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
      Alveolar/Bronchiolar Adenoma         |                   X  X                                                   |          6 |
      Alveolar/Bronchiolar Carcinoma       |                                                                          |          2 |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                        X                                 |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  44                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                +                       +                                 |   5        |
      Adenoma                              |                X                                                         |          1 |
      Carcinoma                            |                                        X                                 |          3 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Uterus   |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                               X              X                           |          2 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangioma                           |       X                                                                  |          1 |
      Lymphoma Malignant Lymphocytic       |                      X                                                   |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |       X                                                                  |          2 |
      Lymphoma Malignant Lymphocytic       |                      X                          X                        |          3 |
      Lymphoma Malignant Mixed             |       X  X     X              X           X  X                           |         14 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  45                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Hepatocellular Carcinoma             |                   X        X                 X                           |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               | X              X        X              X  X        X  X        X  X      |             
      Hepatocellular Adenoma, Multiple     |    X                       X                                             |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +                                                                     |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                       +                  |             
      Squamous Cell Papilloma              |                                                       X                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Capsule, Adenoma                     |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  M  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  46                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +     +     +     +  +           +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   | +  +  +     +           +              +  +     +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +              +                                                      |             
      Iliac, Lymphoma Malignant Mixed      |                                                                          |             
      Inguinal, Lymphoma Malignant Mixed   |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Pancreatic, Lymphoma Malignant Mixed |                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                      X   |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  I  +  +  +  +  +  +  +  M  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |             X                             X  X                 X         |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                        X                                 |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  47                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
          Gland                            |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                       +                  |             
      Adenoma                              |                                                       X                  |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  48                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Hepatocellular Carcinoma             |                                     X                                    |             
      Hepatocellular Carcinoma, Multiple   |                                                    X                 X   |             
      Hepatocellular Adenoma               |    X              X                                                      |             
      Hepatocellular Adenoma, Multiple     |                                                    X     X               |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                               X                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Squamous Cell Papilloma              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                X         |             
      Capsule, Adenoma                     |                               X                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  I  M  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  49                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +     +  +     +  +        +     +  +  +     +  +  +  +     +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |    +                                                                     |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Iliac, Lymphoma Malignant Mixed      |                                                                          |             
      Inguinal, Lymphoma Malignant Mixed   |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Pancreatic, Lymphoma Malignant Mixed |                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |          X        X                       X     X              X         |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  50                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
          Gland                            |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                     X              X                 X   |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                        +                                 |             
      Adenoma                              |                                        X                                 |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  51                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  66        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      |                      X              X                 X                  |          3 |
      Hepatocellular Carcinoma             |                                  X  X  X     X                           |          8 |
      Hepatocellular Carcinoma, Multiple   |                                                                          |          2 |
      Hepatocellular Adenoma               |    X              X                 X  X                                 |         15 |
      Hepatocellular Adenoma, Multiple     |          X                                                               |          5 |
      Lymphoma Malignant Mixed             |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                +                                                         |   2        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Squamous Cell Papilloma              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |       +                                      +                           |   3        |
      Squamous Cell Papilloma              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenoma                              |                                                                          |          1 |
      Capsule, Adenoma                     |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  +  +               |  68        |
      Pheochromocytoma Benign              |                                     X                                    |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenoma                              |                   X                                                      |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  M  M  +  +  +  +  +  M  +  M  +  +  +  +  +  M  M  +  +               |  52        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Follicular Cell, Adenoma             | X                                                                        |          1 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  52                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +     +  +  +  +  +  +  +  +     +  +  +  +  +               |  54        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Blood                                   |                                                                          |  17        |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                            +                                             |   3        |
      Iliac, Lymphoma Malignant Mixed      |                            X                                             |          1 |
      Inguinal, Lymphoma Malignant Mixed   |                            X                                             |          1 |
      Lumbar, Lymphoma Malignant Mixed     |                            X                                             |          1 |
      Mediastinal, Lymphoma Malignant Mixed|                            X                                             |          1 |
      Pancreatic, Lymphoma Malignant Mixed |                            X                                             |          1 |
      Renal, Lymphoma Malignant Mixed      |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M               |  66        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +               |  68        |
      Lymphoma Malignant Mixed             | X                          X                                             |          3 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemangiosarcoma                      | X                                                                        |          1 |
      Lymphoma Malignant Mixed             |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  M  +  +  M  +  +  +  M  +  +  +  M  M  +  +  +               |  58        |
      Lymphoma Malignant Mixed             |                            X                                             |          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        |
      Sarcoma                              |                         X                       X                        |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  53                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 NERVOUS SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Alveolar/Bronchiolar Adenoma         |       X           X        X                       X                     |         13 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
          Multiple                         |                                                                          |          1 |
      Alveolar/Bronchiolar Carcinoma       |       X           X     X                    X                           |          4 |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                  X                                       |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                              X                           |          4 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                               +  +     +                                 |   5        |
      Adenoma                              |                               X        X                                 |          4 |
      Carcinoma                            |                                  X                                       |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +               |  68        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             | X                          X                                             |          3 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  54                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                       X                  |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                          X               |             
      Hepatoblastoma                       |                                                                          |             
      Hepatocellular Carcinoma             |                         X                          X                     |             
      Hepatocellular Carcinoma, Multiple   |       X                                                                  |             
      Hepatocellular Adenoma               |                                  X  X                                    |             
      Hepatocellular Adenoma, Multiple     |                                                 X  X                     |             
      Histiocytic Sarcoma                  |                               X                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                     +                                    |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Prostate |                X                                                         |             
      Hemangiosarcoma                      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Capsule, Adenoma                     |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  55                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  M  M  M  +  +  +  M  M  +  M  +  +  +  +  +  +  +  I  +  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +  +  +     +     +  +     +  +  +  +  +     +  +  +  +     +     +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma                       |                X                                                         |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                    X                     |             
      Histiocytic Sarcoma                  |                               X                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                               +                       +                  |             
      Mediastinal, Histiocytic Sarcoma     |                               X                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                       X                  |             
      Mediastinal, Sarcoma                 |                                                                          |             
      Pancreatic, Sarcoma                  |                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                       X                  |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  I  +  +  +  M  +  M  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  M  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                               X                                          |             
      Lymphoma Malignant Mixed             |                                                       X                  |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                               X                                          |             
      Lymphoma Malignant Mixed             |                                                       X                  |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                       X                  |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  56                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   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                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Prostate |                X                                                         |             
      Alveolar/Bronchiolar Adenoma         |    X                                X           X        X               |             
      Alveolar/Bronchiolar Carcinoma       |                                                 X                       X|             
      Histiocytic Sarcoma                  |                               X                                          |             
      Sarcoma                              |                                                                          |             
      Sarcoma, Metastatic, Mesentery       |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                    +                     |             
      Adenoma                              |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                               X                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                               X                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                       X                  |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  57                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                   X      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                      X                                                   |             
      Hepatoblastoma                       |                                                                          |             
      Hepatocellular Carcinoma             |                   X                                   X     X     X      |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |                                                    X                     |             
      Hepatocellular Adenoma, Multiple     |                   X                             X     X           X      |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X               |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Prostate |                                                                          |             
      Hemangiosarcoma                      |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Capsule, Adenoma                     |                                                                   X      |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  58                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  M  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         |          +     +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
      Adenocarcinoma                       |                                                                          |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                     +                                    |             
      Mediastinal, Histiocytic Sarcoma     |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
      Mediastinal, Sarcoma                 |                                                                          |             
      Pancreatic, Sarcoma                  |                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                          X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X        X      |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X               |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X               |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  59                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   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                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenocarcinoma, Metastatic, Prostate |                                                                          |             
      Alveolar/Bronchiolar Adenoma         |                         X                                   X            |             
      Alveolar/Bronchiolar Carcinoma       |                                     X           X                        |             
      Histiocytic Sarcoma                  |                                                                          |             
      Sarcoma                              |                                                                          |             
      Sarcoma, Metastatic, Mesentery       |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                          +               |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                             +            |             
      Adenoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                          X        X      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  60                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Lymphoma Malignant Mixed             |                                                          X               |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
      Sarcoma                              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      |                                                                          |          2 |
      Hepatoblastoma                       |                                                       X                  |          1 |
      Hepatocellular Carcinoma             |       X  X                                                               |          8 |
      Hepatocellular Carcinoma, Multiple   |                                                                          |          1 |
      Hepatocellular Adenoma               |             X        X     X  X  X                                       |          8 |
      Hepatocellular Adenoma, Multiple     | X                                      X     X        X                  |         10 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
      Sarcoma                              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               | +     +                                                                  |   3        |
      Sarcoma                              |       X                                                                  |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Sarcoma                              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Squamous Cell Papilloma              |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Sarcoma                              |                               X                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenocarcinoma, Metastatic, Prostate |                                                                          |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  61                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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 Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Capsule, Adenoma                     |                            X                                             |          2 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
      Adenoma                              | X                                                                        |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  M  M  +  M  M  M  +  M  +  +  +  +  +  +  +  M  M               |  47        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Follicular Cell, Adenoma             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +        +     +  +  +  +  +  +  +  +  +  +  +               |  53        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenocarcinoma                       |                                                                          |          1 |
      Sarcoma                              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Sarcoma                              |                               X  X                                       |          2 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                               +  +                                       |   5        |
      Mediastinal, Histiocytic Sarcoma     |                                                                          |          1 |
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |          1 |
      Mediastinal, Sarcoma                 |                               X  X                                       |          2 |
      Pancreatic, Sarcoma                  |                                  X                                       |          1 |
      Renal, Lymphoma Malignant Mixed      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          3 |
      Sarcoma                              |                               X  X                                       |          2 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  62                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
      Sarcoma                              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  M  +               |  60        |
      Lymphoma Malignant Lymphocytic       |                            X                                             |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
      Sarcoma                              |                               X                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 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        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenocarcinoma, Metastatic, Prostate |                                                                          |          1 |
      Alveolar/Bronchiolar Adenoma         |                                           X                              |          7 |
      Alveolar/Bronchiolar Carcinoma       |                                  X                                       |          5 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Sarcoma                              |                               X                                          |          1 |
      Sarcoma, Metastatic, Mesentery       |       X                                                                  |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   2        |
      Adenoma                              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  68        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  63                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant Lymphocytic       |                            X                                             |          1 |
      Lymphoma Malignant Mixed             |                                                          X               |          4 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  64                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Hemangiosarcoma                      |                                                                          |             
      Hepatoblastoma, Multiple             |                                                                          |             
      Hepatocellular Carcinoma             |                   X                    X              X                  |             
      Hepatocellular Carcinoma, Multiple   | X                       X                                                |             
      Hepatocellular Adenoma               | X                 X                          X              X  X         |             
      Hepatocellular Adenoma, Multiple     |                         X                                                |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                +         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                X         |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                        X                                 |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  +  M  +  +  +  +  +  M  +  +  +  M  +  M  +  M  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  M  +  M  +  +  +  M  +  +  M  +  +  +  +  M  +  +  +  +  +  +|             
      Pars Intermedia, Carcinoma           |                                           X                              |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  65                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +           +  +  +     +     M  +  +  +  +     +     +  +  +  +     +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Adenoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|             
      Lipoma                               |                               X                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pituitary     |                                                                          |             
          Gland                            |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                   X                    X                                 |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           | X                       X                             X                  |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  66                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  67                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                     X                                    |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                    X                     |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                X                                                         |             
      Hemangiosarcoma                      |                      X                                                   |             
      Hepatoblastoma, Multiple             |                                                                          |             
      Hepatocellular Carcinoma             |    X           X     X              X                                    |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |          X     X              X                                   X      |             
      Hepatocellular Adenoma, Multiple     | X                                         X                              |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                       +                  |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  +  +  +  M  M  M  +  +  M  +  M  +  +  +  +  +  +  M  I  M  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Intermedia, Carcinoma           |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  68                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +   |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Adenoma           |                                     X                 X                  |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                      X                                                   |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                    +                     |             
      Mediastinal, Lymphoma Malignant Mixed|                                                    X                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|             
      Lymphoma Malignant Mixed             |                                     X                                    |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                      X                                                   |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lipoma                               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pituitary     |                                                                          |             
          Gland                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |       X              X                                                   |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       |          X                                                               |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  69                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                     X              X                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  70                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  M               |  67        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangioma                           |                                                                          |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatoblastoma, Multiple             |                X                                                         |          1 |
      Hepatocellular Carcinoma             |          X        X           X        X        X  X  X  X               |         15 |
      Hepatocellular Carcinoma, Multiple   |                                                                          |          2 |
      Hepatocellular Adenoma               |                      X                                X  X               |         12 |
      Hepatocellular Adenoma, Multiple     |          X     X                    X                                    |          6 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  +  M  M               |  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Pars Intermedia, Carcinoma           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +               |  69        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  71                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Penis                                   |             +                                                            |   1        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         |    +     +  +  +  +  +  +  +  +     +  +  +     +  +  +  +               |  55        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  M  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Interstitial Cell, Adenoma           |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
      Mediastinal, Lymphoma Malignant Mixed|                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  67        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  M  +               |  65        |
      Lymphoma Malignant Mixed             |                                        X                                 |          2 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemangiosarcoma                      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   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        |
      Lipoma                               |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Carcinoma, Metastatic, Pituitary     |                                                                          |            |
          Gland                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Alveolar/Bronchiolar Adenoma         |                                           X                              |          5 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
          Multiple                         |                      X                                   X               |          2 |
      Alveolar/Bronchiolar Carcinoma       |                         X                                                |          2 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  72                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                       X                  |          4 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +               |  68        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +               |  68        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Mixed             |                                        X                                 |          3 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  73                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |             X                                                            |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                 X     X                 X|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  +  A  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |             X                                                            |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatoblastoma                       |                                                                          |             
      Hepatoblastoma, Multiple             |                                                             X            |             
      Hepatocellular Carcinoma             | X                                         X           X     X            |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |          X                       X           X  X     X                  |             
      Hepatocellular Adenoma, Multiple     |                   X  X              X              X        X           X|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Hepatoblastoma, Metastatic, Liver    |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma, Metastatic, Spleen  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |             +                                                            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  M  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | I  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  74                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +     +  +  +  +  +     +        +  +  +  +  +  +  +     +     +     +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |                      +              +  +  +  +  +  +                     |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                   X      |             
      Mast Cell Tumor NOS                  |                                                       X                  |             
                                            __________________________________________________________________________|             
   Lymph Node                              |             +              +                                             |             
      Lumbar, Lymphoma Malignant Mixed     |             X                                                            |             
      Renal, Lymphoma Malignant Lymphocytic|                            X                                             |             
      Renal, Lymphoma Malignant Mixed      |             X                                                            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
      Lymphoma Malignant Mixed             |             X     X                    X              X                 X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                   X      |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
      Lymphoma Malignant Mixed             |             X                          X                                 |             
      Mast Cell Tumor NOS                  |                                                       X                  |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  I  +  +  +  +  M  +  +  +  +  M  +  M  I  +  M  +  M  +  M  M  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
      Lymphoma Malignant Mixed             |             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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibroma                              |                                                                          |             
      Hemangiosarcoma                      |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  75                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |          X                                X                              |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                           X                              |             
      Hepatoblastoma, Metastatic, Liver    |                                                             X            |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                           +                              |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                            X                                             |             
      Lymphoma Malignant Mixed             |             X     X                    X        X     X                 X|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  76                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |             X                                                        X   |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Mixed             |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatoblastoma                       |                   X                             X                        |             
      Hepatoblastoma, Multiple             |                                                                          |             
      Hepatocellular Carcinoma             |          X     X           X                                             |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |                X  X        X           X                 X               |             
      Hepatocellular Adenoma, Multiple     |             X                                   X     X     X            |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                   +                                                      |             
      Hepatoblastoma, Metastatic, Liver    |                   X                                                      |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma, Metastatic, Spleen  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                             +            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  M|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                          X               |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  M  +  M  +  M  +  +  +  M  +  M  M  M  M  +  M  +  +  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  77                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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                   |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |       +  +  +  +  +  +  +  +     +     +        +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Blood                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                         X|             
      Mast Cell Tumor NOS                  |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |             
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |             
      Renal, Lymphoma Malignant Mixed      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |             X                                                        X   |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                         X|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
      Mast Cell Tumor NOS                  |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibroma                              |                                                                          |             
      Hemangiosarcoma                      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  78                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                      X                                                   |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                                                          |             
      Hepatoblastoma, Metastatic, Liver    |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant Lymphocytic       |                                                                          |             
      Lymphoma Malignant Mixed             |             X                                                        X   |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  79                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  68        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  66        |
      Lymphoma Malignant Mixed             |                                                                          |          5 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  65        |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hepatoblastoma                       |                         X                       X                        |          4 |
      Hepatoblastoma, Multiple             |                                                                          |          1 |
      Hepatocellular Carcinoma             |                   X                       X     X     X                  |         11 |
      Hepatocellular Carcinoma, Multiple   | X                                                                        |          1 |
      Hepatocellular Adenoma               |                            X     X     X  X        X     X               |         16 |
      Hepatocellular Adenoma, Multiple     |    X           X        X                    X  X                        |         15 |
      Histiocytic Sarcoma                  |                                                       X                  |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                 +                        |   2        |
      Hepatoblastoma, Metastatic, Liver    |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma, Metastatic, Spleen  | X                                                                        |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  67        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  66        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  80                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  M  +  +  M  M  +  +  +  M  +  +  +               |  49        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  64        |
      Pars Intermedia, Adenoma             |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +               |  54        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +               |  65        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Blood                                   |                                                                          |   7        |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  69        |
      Hemangiosarcoma                      |                                                                          |          2 |
      Mast Cell Tumor NOS                  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   2        |
      Lumbar, Lymphoma Malignant Mixed     |                                                                          |          1 |
      Renal, Lymphoma Malignant Lymphocytic|                                                                          |          1 |
      Renal, Lymphoma Malignant Mixed      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  66        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  65        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          7 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Hemangiosarcoma                      | X                                                                        |          3 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          2 |
      Mast Cell Tumor NOS                  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  M  +  +  M  +  M  +  +  +  M  +               |  56        |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  81                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 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        |
      Fibroma                              |          X                                                               |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
                                            __________________________________________________________________________|____________|
   Peripheral Nerve                        |                                     +                                    |   1        |
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                     +                                    |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Alveolar/Bronchiolar Adenoma         |    X                                                     X               |          5 |
      Alveolar/Bronchiolar Carcinoma       | X                                                                        |          1 |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Hepatoblastoma, Metastatic, Liver    |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                       X                  |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                      +                                                   |   2        |
      Adenoma                              |                      X                                                   |          1 |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +               |  67        |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  82                                                               
NTP Experiment-Test: 05150-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                   METHYLPHENIDATE HYDROCHLORIDE                               Date: 04/01/97  
Route: DOSED FEED                                                                                                 Time: 16:31:36  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 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|              |            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +               |  70        |
      Histiocytic Sarcoma                  |                                                       X                  |          1 |
      Lymphoma Malignant Lymphocytic       |                                                                          |          1 |
      Lymphoma Malignant Mixed             |                                                                          |          8 |
 __________________________________________________________________________________________________________________________________ 
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  83                                                               
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