National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/3454

TDMS Study 05040-02 Pathology Tables

NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97
Route: GAVAGE                                                                                                     Time: 10:16:48




       Facility:  American Biogenics Corp.

       Chemical CAS #:  000123319

       Lock Date:  None

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All






































                                                              Page   1

NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 6| 7| 4| 4| 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 4| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 3| 5| 3| 9| 3| 5| 0| 3| 3| 5| 8| 5| 3| 3| 3| 9| 6| 9| 3| 3| 3| 3|             
                                           | 5| 5| 6| 1| 7| 7| 3| 7| 7| 6| 6| 6| 2| 3| 7| 7| 5| 5| 1| 9| 5| 7| 6| 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|             
   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|             
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  A  +  +  +  +|             
      Inflammation, Chronic                |                                                                   2      |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  A  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +     +  +  +     A  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +     +  +  +     A  +  +  +  +     +  +  +  +  A  A  +  +  +  +|             
      Amyloid Deposition                   |                               4                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  A  +  +  +  +|             
      Peyer's Patch, Hyperplasia, Lymphoid |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                                                                          |             
      Congestion                           |                                                                          |             
      Eosinophilic Focus                   |                                                       X        X         |             
      Fatty Change                         | 2                                                                        |             
      Hematopoietic Cell Proliferation     | 1                                                                        |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Focal, Granulomatous   |                                                                          |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |       2                                                                  |             
      Biliary Tract, Inflammation, Chronic |                               2                                          |             
      Kupffer Cell, Hyperplasia            |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               | +              +     +                                +              +  +|             
      Inflammation, Chronic                |                4                                                         |             
      Inflammation, Suppurative            |                                                                          |             
      Fat, Hemorrhage, Focal               |                                                                          |             
      Fat, Necrosis, Focal                 | 4                    2                                4              4  4|             
      Fat, Lymphatic, Hemorrhage, Focal    |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Subacute               |                                                                          |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |          2           2        2        2                       2  2  2   |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   2                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 6| 7| 4| 4| 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 4| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 3| 5| 3| 9| 3| 5| 0| 3| 3| 5| 8| 5| 3| 3| 3| 9| 6| 9| 3| 3| 3| 3|             
                                           | 5| 5| 6| 1| 7| 7| 3| 7| 7| 6| 6| 6| 2| 3| 7| 7| 5| 5| 1| 9| 5| 7| 6| 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|             
   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|             
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Atrioventricular Valve, Inflammation,|                                                                          |             
           Subacute                        |                                                                          |             
      Atrium, Thrombosis                   |                                                                          |             
      Epicardium, Inflammation, Chronic    |                   1                                                      |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Focal                  | 4                                                                        |             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +     +  +  +     +  +  +  +  +     +  M  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +     +  +  +     +  +  M  +  +     +  +  M  +  +  +  +  M  +  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +     +  +  +     +  +  M  +  +     +  +  I  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |    3           3  2           3              1                          3|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Follicular Cell, Hyperplasia         | 2        1                       4                 1                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       X        X                                                         |             
      Fibrosis                             |                                                       4                  |             
      Inflammation, Chronic                |                                                       3                  |             
      Inflammation, Suppurative            |                                                 4                        |             
      Necrosis                             |                                                                          |             
      Thrombosis                           |                                                       X                  |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         |          2                                                               |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Subacute                        |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Hydrometra                           |                                                                          |             
      Endometrium, Hemorrhage              |                                                                          |             
      Endometrium, Hyperplasia, Cystic     | 2  4  3           3  2           2  3  4     3  2  2  2     3     3  2  4|             
      Endometrium, Inflammation,           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   3                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 6| 7| 4| 4| 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 4| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 3| 5| 3| 9| 3| 5| 0| 3| 3| 5| 8| 5| 3| 3| 3| 9| 6| 9| 3| 3| 3| 3|             
                                           | 5| 5| 6| 1| 7| 7| 3| 7| 7| 6| 6| 6| 2| 3| 7| 7| 5| 5| 1| 9| 5| 7| 6| 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|             
   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|             
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
          Suppurative                      |                      3                                                   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Axillary, Hyperplasia, Lymphoid      |                                                                          |             
      Deep Cervical, Hyperplasia, Plasma   |                                                                          |             
          Cell                             |                                                                   4      |             
      Inguinal, Hematopoietic Cell         |                                                                          |             
          Proliferation                    |                   4                                                      |             
      Mediastinal, Hematopoietic Cell      |                                                                          |             
          Proliferation                    |                   4                                                      |             
      Mediastinal, Inflammation,           |                                                                          |             
          Suppurative                      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  +  +     M  +  +     +  +  +  +  +     +  +  +  +  +  M  +  +  +  +|             
      Hyperplasia, Lymphoid                |                   4                                                      |             
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Cyst                                 |                                                                          |             
      Hematopoietic Cell Proliferation     |                   4                                                      |             
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |             
      Thrombosis                           |                   X                                                      |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     | 4                                                     4                 4|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +     +  +  +     M  +  +  +  +     +  +  +  +  M  M  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  M  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Cystic                  |                                                                      2   |             
      Hyperplasia                          | 2        3                                                     3         |             
      Duct, Ectasia                        |    3                                                                     |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                   4                                                      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Fibrous Osteodystrophy               |                   1                          1                           |             
      Joint, Tarsal, Hyperostosis          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Mineralization                       |                   1                          1                           |             
      Cerebrum, Inflammation, Chronic,     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   4                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 6| 7| 4| 4| 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 4| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 3| 5| 3| 9| 3| 5| 0| 3| 3| 5| 8| 5| 3| 3| 3| 9| 6| 9| 3| 3| 3| 3|             
                                           | 5| 5| 6| 1| 7| 7| 3| 7| 7| 6| 6| 6| 2| 3| 7| 7| 5| 5| 1| 9| 5| 7| 6| 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|             
   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|             
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
           Focal                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |          +                                                               |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                     3                                    |             
      Hemorrhage, Focal                    |                                                                          |             
      Inflammation, Chronic                | 3                                                                        |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Mucosa, Inflammation, Chronic        |                                                                          |             
      Nasolacrimal Duct, Foreign Body      |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                  +                                +      |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                   +              +                                +      |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Amyloid Deposition                   |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Inflammation, Chronic                | 1     1  2     2  1  2        1     1        2     1        1  2  2  1   |             
      Cortex, Metaplasia, Osseous          |                                                                          |             
      Cortex, Necrosis, Focal              |                                                                          |             
      Renal Tubule, Pigmentation,          |                                                                          |             
          Hemosiderin                      |                                                       4                  |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +     +  +  +     +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|             
      Cytomegaly                           |                                                                          |             
      Submucosa, Inflammation, Chronic     | 1     1  1           2        2        2           2           1  2      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   5                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 2| 7| 6| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 7| 4| 4| 7| 7| 7| 7| 5|             
                             DAY ON TEST   | 3| 3| 3| 5| 9| 3| 3| 5| 5| 7| 3| 3| 3| 3| 5| 3| 3| 3| 5| 3| 3| 3| 3| 3| 5|             
                                           | 7| 6| 5| 7| 3| 5| 7| 7| 7| 2| 6| 6| 5| 5| 7| 7| 6| 5| 7| 1| 6| 6| 5| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +     +  +  +        M  +  +  +  +     +  +  +     A  +  +  +  +  A|             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +     A  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +        +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +        +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +        +  +        A  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +     A  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +        +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +        +  +        A  +  +  +  +     +  +  +     +  +  +  +  +  A|             
      Amyloid Deposition                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +        +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Peyer's Patch, Hyperplasia, Lymphoid |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Angiectasis                          |                                                                   1      |             
      Basophilic Focus                     |                               X                                          |             
      Congestion                           |                            2                                             |             
      Eosinophilic Focus                   |                                                                X         |             
      Fatty Change                         |                                                                1         |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Inflammation, Chronic                |                                     1        1  2                        |             
      Inflammation, Focal, Granulomatous   |                                                                          |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |                                                                         1|             
      Biliary Tract, Inflammation, Chronic |                                                                          |             
      Kupffer Cell, Hyperplasia            |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |       +                       +     +        +     +           +  +     +|             
      Inflammation, Chronic                |                                              3                           |             
      Inflammation, Suppurative            |                                                                          |             
      Fat, Hemorrhage, Focal               |                                              3                           |             
      Fat, Necrosis, Focal                 |       4                             4                          3  4      |             
      Fat, Lymphatic, Hemorrhage, Focal    |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                    2                     |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +     +  +  +        M  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Inflammation, Chronic                |                                     4                                    |             
      Inflammation, Subacute               |                                                                          |             
      Duct, Ectasia                        |                                     4                                    |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Inflammation, Chronic                | 2  2  1        1              2  2  1  3     1  1  2        1  2     2   |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +     +  +  +        +  +  +  +  +     +  +  +     M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +     +  +  +        +  +  +  +  +     +  +  +        +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +     +  +  +        +  +  +  +  +     +  +  +        +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   6                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 2| 7| 6| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 7| 4| 4| 7| 7| 7| 7| 5|             
                             DAY ON TEST   | 3| 3| 3| 5| 9| 3| 3| 5| 5| 7| 3| 3| 3| 3| 5| 3| 3| 3| 5| 3| 3| 3| 3| 3| 5|             
                                           | 7| 6| 5| 7| 3| 5| 7| 7| 7| 2| 6| 6| 5| 5| 7| 7| 6| 5| 7| 1| 6| 6| 5| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Cardiomyopathy                       |    1                                                                     |             
      Inflammation, Chronic                |                            3                                             |             
      Atrioventricular Valve, Inflammation,|                                                                          |             
           Subacute                        |                                                                          |             
      Atrium, Thrombosis                   |    X                                                                     |             
      Epicardium, Inflammation, Chronic    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Degeneration, Focal                  |                                                                2         |             
      Hyperplasia, Focal                   |                                  3              2  2                     |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  M  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +     +  +  +        M  +  +  +  +     +  +  +     M  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +     M  +  +        M  +  M  M  +     +  M  +     +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |       3                          2     3        2              2     2   |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Inflammation, Chronic                |                                              1                           |             
      Follicular Cell, Hyperplasia         |                   1              2  1        1                           |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Cyst                                 |                   X           X     X  X     X                       X   |             
      Fibrosis                             |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
      Necrosis                             |                                                                          |             
      Thrombosis                           |                                                                          |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         |                                                    1        1        2   |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Subacute                        |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +     +  +  +        +  M  +  +  +     +  +  +     +  +  +  +  +  +|             
      Hydrometra                           | 3     3                                                                  |             
      Endometrium, Hemorrhage              |                                                                3         |             
      Endometrium, Hyperplasia, Cystic     |    2              3              2  2  4     1  4  2        4  3  4  2   |             
      Endometrium, Inflammation,           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   7                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 2| 7| 6| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 7| 4| 4| 7| 7| 7| 7| 5|             
                             DAY ON TEST   | 3| 3| 3| 5| 9| 3| 3| 5| 5| 7| 3| 3| 3| 3| 5| 3| 3| 3| 5| 3| 3| 3| 3| 3| 5|             
                                           | 7| 6| 5| 7| 3| 5| 7| 7| 7| 2| 6| 6| 5| 5| 7| 7| 6| 5| 7| 1| 6| 6| 5| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
          Suppurative                      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Axillary, Hyperplasia, Lymphoid      |                                                                          |             
      Deep Cervical, Hyperplasia, Plasma   |                                                                          |             
          Cell                             |                                                                          |             
      Inguinal, Hematopoietic Cell         |                                                                          |             
          Proliferation                    |                                                                          |             
      Mediastinal, Hematopoietic Cell      |                                                                          |             
          Proliferation                    |                                                                          |             
      Mediastinal, Inflammation,           |                                                                          |             
          Suppurative                      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +     +  +  +        M  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +     M  +  +        +  +  +  +  +     M  +  +     +  +  +  +  +  +|             
      Congestion                           |    4                                                                     |             
      Cyst                                 |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                            3        4                                    |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +     A  M  +        M  +  +  +  +     +  +  +     +  +  +  +  +  M|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +     M  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Hyperplasia, Cystic                  |                                                                          |             
      Hyperplasia                          | 2              3                 2                                       |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Ulcer                                |                                              4                           |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Fibrous Osteodystrophy               |    1                                1              1                     |             
      Joint, Tarsal, Hyperostosis          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Mineralization                       |    1                                1              1                     |             
      Cerebrum, Inflammation, Chronic,     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   8                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 4| 2| 7| 6| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 7| 4| 4| 7| 7| 7| 7| 5|             
                             DAY ON TEST   | 3| 3| 3| 5| 9| 3| 3| 5| 5| 7| 3| 3| 3| 3| 5| 3| 3| 3| 5| 3| 3| 3| 3| 3| 5|             
                                           | 7| 6| 5| 7| 3| 5| 7| 7| 7| 2| 6| 6| 5| 5| 7| 7| 6| 5| 7| 1| 6| 6| 5| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
           Focal                           |                                     2                                    |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  M|             
      Mucosa, Inflammation, Chronic        |                                                                          |             
      Nasolacrimal Duct, Foreign Body      |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +     A  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +     +  +  +        +  +  +  +  +     +  +  +     +  +  +  +  +  +|             
      Amyloid Deposition                   |             4     4                                                      |             
      Glomerulosclerosis                   |       3                                                                  |             
      Inflammation, Chronic                | 2  2  2        1           1        2  1     2     2        2  1  1  1   |             
      Cortex, Metaplasia, Osseous          |                                                                          |             
      Cortex, Necrosis, Focal              |                                                                          |             
      Renal Tubule, Pigmentation,          |                                                                          |             
          Hemosiderin                      |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +     M  +  +        +  M  +  +  +     +  +  +     +  +  +  +  +  +|             
      Cytomegaly                           |                2                                                         |             
      Submucosa, Inflammation, Chronic     | 2              2                 2  2  2     2  2  3        2  1  1  1   |             
 _____________________________________________________________________________________________________________________|             
                                                             Page   9                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 7| 7| 7| 7| 4| 7| 7| 5| 5| 4|                             |            |
                             DAY ON TEST   | 3| 3| 3| 7| 6| 3| 3| 3| 3| 5| 3| 3| 9| 4| 5|                             |            |
                                           | 6| 6| 5| 6| 4| 7| 7| 6| 5| 7| 7| 6| 6| 0| 7|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |      A     |
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  A  +  +  +  +     +  +  +  +                                 |  50        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Intestine Large                         | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  53        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  M     +  +  +  +                                 |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  53        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  49        |
      Amyloid Deposition                   |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  52        |
      Peyer's Patch, Hyperplasia, Lymphoid | 4                                                                        |      1  4.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Angiectasis                          |                                                                          |      1  1.0|
      Basophilic Focus                     |                X                                                         |      2     |
      Congestion                           |                                                                          |      1  2.0|
      Eosinophilic Focus                   |                                                                          |      3     |
      Fatty Change                         |                3                       1                                 |      4  1.8|
      Hematopoietic Cell Proliferation     |    4     2                                                               |      3  2.3|
      Inflammation, Chronic                |          2        1                                                      |      5  1.4|
      Inflammation, Focal, Granulomatous   |                4                                                         |      1  4.0|
      Mixed Cell Focus                     |             X                                                            |      1     |
      Necrosis                             |                                     3                                    |      3  2.0|
      Biliary Tract, Inflammation, Chronic |                                                                          |      1  2.0|
      Kupffer Cell, Hyperplasia            |             2                                                            |      1  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               | +  +                    +        +  +                                    |  19        |
      Inflammation, Chronic                |                                                                          |      2  3.5|
      Inflammation, Suppurative            |    4                                                                     |      1  4.0|
      Fat, Hemorrhage, Focal               |                                                                          |      1  3.0|
      Fat, Necrosis, Focal                 |                         4        3                                       |     11  3.6|
      Fat, Lymphatic, Hemorrhage, Focal    | 4                                                                        |      1  4.0|
      Perivascular, Inflammation, Chronic  |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
      Inflammation, Subacute               |    4                                                                     |      1  4.0|
      Duct, Ectasia                        |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  M  +  +  +  +     +  +  +  +                                 |  54        |
      Inflammation, Chronic                | 2        3     2     1                                                   |     25  1.8|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  10                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 7| 7| 7| 7| 4| 7| 7| 5| 5| 4|                             |            |
                             DAY ON TEST   | 3| 3| 3| 7| 6| 3| 3| 3| 3| 5| 3| 3| 9| 4| 5|                             |            |
                                           | 6| 6| 5| 6| 4| 7| 7| 6| 5| 7| 7| 6| 6| 0| 7|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |      A     |
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Stomach                                 | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +        +  +  +                                 |  53        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Cardiomyopathy                       |                                                                          |      1  1.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Atrioventricular Valve, Inflammation,|                                                                          |            |
           Subacute                        |                                        4                                 |      1  4.0|
      Atrium, Thrombosis                   |                                                                          |      1     |
      Epicardium, Inflammation, Chronic    |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Degeneration, Focal                  |                                                                          |      2  3.0|
      Hyperplasia, Focal                   |                                                                          |      3  2.3|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  | +  +  +  M  +  +  +  +  +     M  +  +  +                                 |  51        |
      Hyperplasia, Focal                   |                2                                                         |      1  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  M     +  +  +  +                                 |  51        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  M  +  +  +  +  M  +     +  +  +  M                                 |  40        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  I     +  +  +  +                                 |  52        |
      Pars Distalis, Angiectasis           |                                        2                                 |      1  2.0|
      Pars Distalis, Hyperplasia, Focal    |                   3                                                      |     13  2.5|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Inflammation, Chronic                |          2  2                                                            |      3  1.7|
      Follicular Cell, Hyperplasia         | 2     1  3     1              3                                          |     13  1.8|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |          +                                                               |   1        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Cyst                                 | X     X        X                 X                                       |     12     |
      Fibrosis                             |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
      Necrosis                             |                                        3                                 |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  11                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 7| 7| 7| 7| 4| 7| 7| 5| 5| 4|                             |            |
                             DAY ON TEST   | 3| 3| 3| 7| 6| 3| 3| 3| 3| 5| 3| 3| 9| 4| 5|                             |            |
                                           | 6| 6| 5| 6| 4| 7| 7| 6| 5| 7| 7| 6| 6| 0| 7|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |      A     |
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Thrombosis                           |                                                                          |      1     |
      Periovarian Tissue, Inflammation,    |                                                                          |            |
           Chronic                         | 2                                                                        |      5  1.6|
      Periovarian Tissue, Inflammation,    |                                                                          |            |
           Subacute                        |    3                                                                     |      1  3.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
      Hydrometra                           |                                                                          |      2  3.0|
      Endometrium, Hemorrhage              |                                                                          |      1  3.0|
      Endometrium, Hyperplasia, Cystic     | 4  4  3  3        3  3  3     4  2                                       |     37  2.9|
      Endometrium, Inflammation,           |                                                                          |            |
          Suppurative                      |    3                                                                     |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Axillary, Hyperplasia, Lymphoid      |          4                                                               |      1  4.0|
      Deep Cervical, Hyperplasia, Plasma   |                                                                          |            |
          Cell                             |                                                                          |      1  4.0|
      Inguinal, Hematopoietic Cell         |                                                                          |            |
          Proliferation                    |                                                                          |      1  4.0|
      Mediastinal, Hematopoietic Cell      |                                                                          |            |
          Proliferation                    |                                                                          |      1  4.0|
      Mediastinal, Inflammation,           |                                                                          |            |
          Suppurative                      |    4                                                                     |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  M  +  +  +  +     +  +  +  +                                 |  50        |
      Hyperplasia, Lymphoid                |                4                                                         |      2  4.0|
      Hyperplasia, Lymphoid, Plasma Cell   |          4                                                               |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  M  +  +  +     +  +  +  +                                 |  52        |
      Congestion                           |                                                                          |      1  4.0|
      Cyst                                 |             X                                                            |      1     |
      Hematopoietic Cell Proliferation     |                                                                          |      1  4.0|
      Hyperplasia, Lymphoid, Plasma Cell   |          4                                                               |      1  4.0|
      Thrombosis                           |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Hematopoietic Cell Proliferation     |    4     4                                                               |      7  3.9|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  M  +  +  +  +  M     +  +  M  M                                 |  44        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  +  +  +  +  +  +  +  +     +  +  +  +                                 |  52        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  12                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 7| 7| 7| 7| 4| 7| 7| 5| 5| 4|                             |            |
                             DAY ON TEST   | 3| 3| 3| 7| 6| 3| 3| 3| 3| 5| 3| 3| 9| 4| 5|                             |            |
                                           | 6| 6| 5| 6| 4| 7| 7| 6| 5| 7| 7| 6| 6| 0| 7|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |      A     |
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Hyperplasia, Cystic                  |                                                                          |      1  2.0|
      Hyperplasia                          |          4  3  2                                                         |      9  2.7|
      Duct, Ectasia                        |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Ulcer                                |                                                                          |      2  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Fibrous Osteodystrophy               |                                                                          |      5  1.0|
      Joint, Tarsal, Hyperostosis          |                               X                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Mineralization                       |                                                                          |      5  1.0|
      Cerebrum, Inflammation, Chronic,     |                                                                          |            |
           Focal                           |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |       +                 +              +                                 |   4        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Congestion                           |                                                                          |      1  3.0|
      Hemorrhage, Focal                    |                                        4                                 |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Perivascular, Inflammation, Chronic  | 2              3                                                         |      2  2.5|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
      Mucosa, Inflammation, Chronic        |    2                                                                     |      1  2.0|
      Nasolacrimal Duct, Foreign Body      |          4                                                               |      1  4.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  54        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                   +                                                      |   1        |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   3        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  55        |
      Amyloid Deposition                   |                                                                          |      2  4.0|
      Glomerulosclerosis                   |                                                                          |      1  3.0|
      Inflammation, Chronic                | 2     2     1  2  1           2  1     3                                 |     35  1.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  13                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 7| 7| 7| 7| 4| 7| 7| 5| 5| 4|                             |            |
                             DAY ON TEST   | 3| 3| 3| 7| 6| 3| 3| 3| 3| 5| 3| 3| 9| 4| 5|                             |            |
                                           | 6| 6| 5| 6| 4| 7| 7| 6| 5| 7| 7| 6| 6| 0| 7|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |      A     |
    VEHICLE                                | 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Cortex, Metaplasia, Osseous          |                3                                                         |      1  3.0|
      Cortex, Necrosis, Focal              |                                        4                                 |      1  4.0|
      Renal Tubule, Pigmentation,          |                                                                          |            |
          Hemosiderin                      |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +     +  +  +  +                                 |  53        |
      Cytomegaly                           |                                                                          |      1  2.0|
      Submucosa, Inflammation, Chronic     | 1     2  1  1  2  2  2                                                   |     28  1.7|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  14                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 4| 4| 4| 7| 7| 7| 7| 4| 6| 7| 7| 7| 5| 7| 7| 7| 6| 4| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 5| 5| 5| 0| 3| 3| 3| 3| 5| 3| 3| 3| 3| 6| 3| 3| 3| 8| 5| 3| 3| 3| 5| 5|             
                                           | 6| 7| 7| 7| 9| 7| 7| 6| 5| 7| 0| 7| 6| 5| 1| 7| 7| 6| 3| 7| 5| 5| 5| 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   | 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|             
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Gallbladder                             |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Large                         |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  |             +                 +           +           +                  |             
      Colon, Serosa, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 |             M                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Small                         |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               |             +                 +           +           +                  |             
      Muscularis, Inflammation, Acute      |                                                                          |             
      Serosa, Ileum, Jejunum, Inflammation,|                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                |                               +           +           +                  |             
                                            __________________________________________________________________________|             
   Liver                                   | +           +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     | X                                               X           X            |             
      Cyst                                 |                                                                          |             
      Eosinophilic Focus                   |                                                                          |             
      Fatty Change                         |                                                             3            |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Necrosis                             |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                               +     +  +                          +      |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
      Necrosis, Focal                      |                                                                          |             
      Fat, Necrosis, Focal                 |                                     4  4                          4      |             
                                            __________________________________________________________________________|             
   Pancreas                                |             +     +           +           +           +                  |             
      Inflammation, Chronic                |                   3                                                      |             
      Duct, Ectasia                        |                   4                                                      |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +           +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                3     2  1     1  2  2  2  2  1     2  2     2  2  2      |             
                                            __________________________________________________________________________|             
   Stomach                                 |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      |             +                 +           +           +                  |             
      Erosion, Focal                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   |             +                 +           +        +  +                  |             
      Hemorrhage                           |                                                                          |             
      Atrium, Thrombosis                   |                                                    X                     |             
      Coronary Artery, Inflammation,       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  15                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 4| 4| 4| 7| 7| 7| 7| 4| 6| 7| 7| 7| 5| 7| 7| 7| 6| 4| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 5| 5| 5| 0| 3| 3| 3| 3| 5| 3| 3| 3| 3| 6| 3| 3| 3| 8| 5| 3| 3| 3| 5| 5|             
                                           | 6| 7| 7| 7| 9| 7| 7| 6| 5| 7| 0| 7| 6| 5| 1| 7| 7| 6| 3| 7| 5| 5| 5| 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   | 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|             
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
          Chronic                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +           +     +  +        +  +  +  +  +        +  +     +  +  +      |             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    |                                        3                                 |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +           +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                      2                             2                     |             
      Polyarteritis                        |                                                                          |             
      Follicular Cell, Hyperplasia         | 2              1  2  4  2     4  2  2  2     1  1  4        2     3      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +           +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Angiectasis                          |                      4                                                   |             
      Cyst                                 |             X           X     X              X     X  X           X      |             
      Hemorrhage                           |                                                                          |             
      Artery, Periovarian Tissue,          |                                                                          |             
          Inflammation, Chronic            |                                                    4                     |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         | 3                                                              3         |             
      Periovarian Tissue, Necrosis         |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  |             +     +     +     +     +     +     +     +           +      |             
      Inflammation, Chronic                |                                                                          |             
      Endometrium, Hyperplasia, Cystic     |                   3     4           3                 4           4      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Lymph Node                              |             +     +           +           +           +           +      |             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
      Iliac, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                                                                          |             
      Mediastinal, Hyperplasia, Lymphoid   |                   4                                                      |             
      Renal, Hemorrhage                    |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  |             +                 +           +           +                  |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  16                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 4| 4| 4| 7| 7| 7| 7| 4| 6| 7| 7| 7| 5| 7| 7| 7| 6| 4| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 5| 5| 5| 0| 3| 3| 3| 3| 5| 3| 3| 3| 3| 6| 3| 3| 3| 8| 5| 3| 3| 3| 5| 5|             
                                           | 6| 7| 7| 7| 9| 7| 7| 6| 5| 7| 0| 7| 6| 5| 1| 7| 7| 6| 3| 7| 5| 5| 5| 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   | 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|             
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Lymphoid                |                               4                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  |             +     +           +           +           M           +      |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                   4                                                      |             
                                            __________________________________________________________________________|             
   Spleen                                  |             +                 +           +           +                  |             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Pigmentation, Hemosiderin            |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  |             +                 M           +           +           M      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +           +  +              +  +        +           +                  |             
      Hyperplasia                          |                                                       2                  |             
                                            __________________________________________________________________________|             
   Skin                                    |             +                 +           +           +                  |             
      Abdominal, Subcutaneous Tissue,      |                                                                          |             
          Abscess                          |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    |             +                 +           +           +                  |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                               +                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   |             +                 +           +           +                  |             
      Cerebrum, Hemorrhage                 |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                           +                              |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +           +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                                                                   1      |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolus, Hyperplasia, Macrophage    |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    |             +                 +           +           +                  |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 |             +                 +           +           +                  |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                +     +                                                   |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  |             +                 +           +           +                  |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  17                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 4| 4| 4| 7| 7| 7| 7| 4| 6| 7| 7| 7| 5| 7| 7| 7| 6| 4| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 5| 5| 5| 0| 3| 3| 3| 3| 5| 3| 3| 3| 3| 6| 3| 3| 3| 8| 5| 3| 3| 3| 5| 5|             
                                           | 6| 7| 7| 7| 9| 7| 7| 6| 5| 7| 0| 7| 6| 5| 1| 7| 7| 6| 3| 7| 5| 5| 5| 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   | 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|             
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Inflammation, Chronic                |                               1           2           2                  |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         |             +                 +           +           +                  |             
      Submucosa, Inflammation, Chronic     |                                           3                              |             
      Subserosa, Inflammation, Chronic     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  18                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 5| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 3| 3| 3| 5| 3| 3| 3| 1| 1| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3|             
                                           | 5| 5| 9| 1| 8| 5| 5| 5| 4| 7| 6| 6| 5| 7| 6| 7| 7| 6| 5| 8| 7| 6| 6| 6| 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|             
   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| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    50 MG/KG                               | 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Gallbladder                             |       +  A  +           M              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Large                         |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  |       +  A  +           +              M  +              +               |             
      Colon, Serosa, Inflammation, Chronic |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +     +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               |       +  +  +           +              +  +              +               |             
      Muscularis, Inflammation, Acute      |                                        3                                 |             
      Serosa, Ileum, Jejunum, Inflammation,|                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +     +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          | 2                                                     3                  |             
      Basophilic Focus                     | X                             X                 X                        |             
      Cyst                                 |                                                          X               |             
      Eosinophilic Focus                   |                                                       X                  |             
      Fatty Change                         |                                              2                           |             
      Hematopoietic Cell Proliferation     |                                                                         4|             
      Hyperplasia, Lymphoid                |                                  3                                       |             
      Inflammation, Chronic                |                               1                                          |             
      Necrosis                             |                                        3                                2|             
                                            __________________________________________________________________________|             
   Mesentery                               |          +  +           +     +        +                                 |             
      Inflammation, Chronic                |                                        4                                 |             
      Inflammation, Suppurative            |                                                                          |             
      Necrosis, Focal                      |             4                                                            |             
      Fat, Necrosis, Focal                 |          3                    4                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                |       +  +  +           +              +  +              +               |             
      Inflammation, Chronic                |          2                                                               |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                | 2        2  1     2  2        2     1        2        2     1     2  2  2|             
                                            __________________________________________________________________________|             
   Stomach                                 |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      |       +  +  +           +              +  +              M               |             
      Erosion, Focal                       |                                        3                                 |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   |       +  +  +           +              +  +              +               |             
      Hemorrhage                           |                                                                          |             
      Atrium, Thrombosis                   |                                                                          |             
      Coronary Artery, Inflammation,       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  19                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 5| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 3| 3| 3| 5| 3| 3| 3| 1| 1| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3|             
                                           | 5| 5| 9| 1| 8| 5| 5| 5| 4| 7| 6| 6| 5| 7| 6| 7| 7| 6| 5| 8| 7| 6| 6| 6| 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|             
   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| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    50 MG/KG                               | 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
          Chronic                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           |       +  +  +           +              M  +              M               |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   |       +  +  +           +                 +                              |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  |       +  +  +           +                 +                              |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       |       +  M  +           +              M  M              +               |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +     +  +  +           M     +        M  +           +  +  M           +|             
      Pars Distalis, Angiectasis           |       2  2                                                               |             
      Pars Distalis, Hyperplasia, Focal    |             3                                                            |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                               3                 2                        |             
      Polyarteritis                        |                                           2                              |             
      Follicular Cell, Hyperplasia         | 3  2  2  2  2  3  2  2        4  1  3     1  2  3  2  2  2  2  1  2  2  1|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |                                           M                              |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Cyst                                 |                                                             X     X  X   |             
      Hemorrhage                           |                                                                         4|             
      Artery, Periovarian Tissue,          |                                                                          |             
          Inflammation, Chronic            |                                                                          |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         |       2                                            2                     |             
      Periovarian Tissue, Necrosis         |                                                          2               |             
                                            __________________________________________________________________________|             
   Uterus                                  |       +  +  +  +  +     +        +     +  +  +  +        +  +            |             
      Inflammation, Chronic                |                                                                          |             
      Endometrium, Hyperplasia, Cystic     |          4  2  3  3              3     3  2  3  4        3  4            |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +  +           +     +        +  +              +           +   |             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
      Iliac, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                                                                          |             
      Mediastinal, Hyperplasia, Lymphoid   |                               4                                          |             
      Renal, Hemorrhage                    | 4                                                                        |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  |       +  +  +           +              +  +              +               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  20                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 5| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 3| 3| 3| 5| 3| 3| 3| 1| 1| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3|             
                                           | 5| 5| 9| 1| 8| 5| 5| 5| 4| 7| 6| 6| 5| 7| 6| 7| 7| 6| 5| 8| 7| 6| 6| 6| 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|             
   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| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    50 MG/KG                               | 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  |    +  +  +  +           +              +  +              +               |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                        4                                 |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  M  +           +        +     +  +           +  +  +        +   |             
      Fibrosis                             |                                        4                                 |             
      Hematopoietic Cell Proliferation     |                         4                                                |             
      Hyperplasia, Lymphoid                |                                  3                                       |             
      Pigmentation, Hemosiderin            |                                  4                                       |             
                                            __________________________________________________________________________|             
   Thymus                                  |       +  +  +           +              +  +              +               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +     +  +  M           +              +  +              +              +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    |       +  +  +           +              +  +              +               |             
      Abdominal, Subcutaneous Tissue,      |                                                                          |             
          Abscess                          |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    |       +  +  +           +              +  +              +               |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                         +                                                |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   |       +  +  +           +              +  +              +               |             
      Cerebrum, Hemorrhage                 |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                               1                                          |             
      Alveolus, Hyperplasia, Macrophage    |                               3                                          |             
                                            __________________________________________________________________________|             
   Nose                                    |       +  +  +           +              +  +              +               |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                         2                                                |             
                                            __________________________________________________________________________|             
   Trachea                                 |       +  +  +           +              +  +              +               |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  |       +  +  +           +              +  +              +               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  21                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 5| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 3| 3| 3| 5| 3| 3| 3| 1| 1| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3|             
                                           | 5| 5| 9| 1| 8| 5| 5| 5| 4| 7| 6| 6| 5| 7| 6| 7| 7| 6| 5| 8| 7| 6| 6| 6| 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|             
   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| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    50 MG/KG                               | 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Inflammation, Chronic                |       1  1  1                                                            |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         |       +  +  +           +              +  +              +               |             
      Submucosa, Inflammation, Chronic     |       1  2                                                               |             
      Subserosa, Inflammation, Chronic     |                         2                                                |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  22                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 6| 6| 4| 7| 7| 7| 7| 6|                             |            |
                             DAY ON TEST   | 3| 3| 8| 5| 4| 3| 3| 6| 0| 5| 3| 3| 3| 3| 4|                             |            |
                                           | 7| 7| 0| 7| 0| 7| 6| 0| 6| 7| 7| 6| 5| 5| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |      A     |
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               |       +     +        +  +                 +                              |  16        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             |       +     +        A  M                 +                              |  12        |
                                            __________________________________________________________________________|____________|
   Intestine Large                         |       +     +        A  +                 +                              |  15        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  |       +     +           +                 +                              |  13        |
      Colon, Serosa, Inflammation, Chronic |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  |       +     +                             +                              |  14        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 |       +     +           +                 +                              |  14        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         |       +     +        A  +                 +                              |  16        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               |       +     +           +                 +                              |  15        |
      Muscularis, Inflammation, Acute      |                                                                          |      1  3.0|
      Serosa, Ileum, Jejunum, Inflammation,|                                                                          |            |
           Chronic                         |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  |       +     A                             +                              |  14        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                |       +     A                             +                              |  12        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +     +  +  +  +  +     +  +  +  +  +                              |  55        |
      Angiectasis                          |                                                                          |      2  2.5|
      Basophilic Focus                     |                                                                          |      6     |
      Cyst                                 |                                                                          |      1     |
      Eosinophilic Focus                   |                   X                    X                                 |      3     |
      Fatty Change                         |                                                                          |      2  2.5|
      Hematopoietic Cell Proliferation     |                                                                          |      1  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Inflammation, Chronic                |    1                    1     2                                          |      4  1.3|
      Necrosis                             |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                         +     +           +                              |  12        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
      Inflammation, Suppurative            |                         4                                                |      1  4.0|
      Necrosis, Focal                      |                                                                          |      1  4.0|
      Fat, Necrosis, Focal                 |                               4                                          |      6  3.8|
                                            __________________________________________________________________________|____________|
   Pancreas                                |       +     +        A  +                 +                              |  16        |
      Inflammation, Chronic                |                         3                                                |      3  2.7|
      Duct, Ectasia                        |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +     +  +  +  +  +     +  +  +  +  M                              |  54        |
      Inflammation, Chronic                | 2     2        2  2           2  1  2                                    |     34  1.8|
                                            __________________________________________________________________________|____________|
   Stomach                                 |       +     +        A  +        +     +  +                              |  17        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    |       +     +           +        +     +  +                              |  17        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      |       +     +           +        +     +  +                              |  16        |
      Erosion, Focal                       |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  23                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 6| 6| 4| 7| 7| 7| 7| 6|                             |            |
                             DAY ON TEST   | 3| 3| 8| 5| 4| 3| 3| 6| 0| 5| 3| 3| 3| 3| 4|                             |            |
                                           | 7| 7| 0| 7| 0| 7| 6| 0| 6| 7| 7| 6| 5| 5| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |      A     |
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   |       +     +        +  +                 +                              |  17        |
      Hemorrhage                           |             3                                                            |      1  3.0|
      Atrium, Thrombosis                   |                                                                          |      1     |
      Coronary Artery, Inflammation,       |                                                                          |            |
          Chronic                          |             3                                                            |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           |       +     +        +  M                 +                              |  13        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   |       +     +        +                    +                              |  13        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  |       +     +        M                    M                              |  11        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      |       +     +        A  +                 +                              |  15        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       |       +     +        +  +                 +                              |  13        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         |    +  +     +        +  +        +        M                              |  29        |
      Pars Distalis, Angiectasis           |                                                                          |      2  2.0|
      Pars Distalis, Hyperplasia, Focal    |       3                          3                                       |      4  3.0|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +     +  +  +  +  +     +  +  +  +  +                              |  55        |
      Inflammation, Chronic                |                                                                          |      4  2.3|
      Polyarteritis                        |                                                                          |      1  2.0|
      Follicular Cell, Hyperplasia         | 2  3  1        3  1  3        1  2  1  2  1                              |     47  2.1|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +     +  +  M  +  M     +  +  +  +  +                              |  53        |
      Angiectasis                          |                                                                          |      1  4.0|
      Cyst                                 |                      X                 X                                 |     12     |
      Hemorrhage                           |                                                                          |      1  4.0|
      Artery, Periovarian Tissue,          |                                                                          |            |
          Inflammation, Chronic            |                                                                          |      1  4.0|
      Periovarian Tissue, Inflammation,    |                                                                          |            |
           Chronic                         |                2                                                         |      5  2.4|
      Periovarian Tissue, Necrosis         |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +     +     +     +  +  +                 +                              |  29        |
      Inflammation, Chronic                |                         4                                                |      1  4.0|
      Endometrium, Hyperplasia, Cystic     | 3                 4                                                      |     18  3.3|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  24                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 6| 6| 4| 7| 7| 7| 7| 6|                             |            |
                             DAY ON TEST   | 3| 3| 8| 5| 4| 3| 3| 6| 0| 5| 3| 3| 3| 3| 4|                             |            |
                                           | 7| 7| 0| 7| 0| 7| 6| 0| 6| 7| 7| 6| 5| 5| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |      A     |
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             |       +     +        +  +                 +                              |  16        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |       +     +        +  +                 +                              |  22        |
      Hyperplasia, Plasma Cell             |                         3                                                |      1  3.0|
      Axillary, Hyperplasia, Plasma Cell   |                         4                                                |      1  4.0|
      Iliac, Hematopoietic Cell            |                                                                          |            |
          Proliferation                    |                         4                                                |      1  4.0|
      Mediastinal, Hyperplasia, Lymphoid   |                                                                          |      2  4.0|
      Renal, Hemorrhage                    |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |       +     +        +  +                 +                              |  16        |
      Hyperplasia, Lymphoid                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |       M     +        +  +                 +                              |  17        |
      Hematopoietic Cell Proliferation     |                         4                                                |      1  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      2  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  |       +     +        +  +              +  +                              |  22        |
      Fibrosis                             |                                                                          |      1  4.0|
      Hematopoietic Cell Proliferation     |                         4                                                |      2  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Pigmentation, Hemosiderin            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  |       +     M        +  M                 +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           |       +     +        +  +                 +                              |  20        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Skin                                    |       +     +        +  +                 +                              |  16        |
      Abdominal, Subcutaneous Tissue,      |                                                                          |            |
          Abscess                          |                         4                                                |      1  4.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Suppurative                     |                         3                                                |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    |       +     +        +  +                 +                              |  16        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   |       +     +        +  +                 +                              |  16        |
      Cerebrum, Hemorrhage                 |             3                                                            |      1  3.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                      +                                                   |   2        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  25                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 6| 6| 4| 7| 7| 7| 7| 6|                             |            |
                             DAY ON TEST   | 3| 3| 8| 5| 4| 3| 3| 6| 0| 5| 3| 3| 3| 3| 4|                             |            |
                                           | 7| 7| 0| 7| 0| 7| 6| 0| 6| 7| 7| 6| 5| 5| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |      A     |
    50 MG/KG                               | 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +     +  +  +  +  +     +  +  +  +  +                              |  55        |
      Inflammation, Chronic                |                                                                          |      1  1.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      1  1.0|
      Alveolus, Hyperplasia, Macrophage    |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Nose                                    |       +     +        +  +                 +                              |  16        |
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic                         |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 |       +     +        +  +                 +                              |  16        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                               +                                          |   3        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  |       +     +        +  +                 +                              |  16        |
      Inflammation, Chronic                |       2                 2                                                |      8  1.5|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         |       +     +        +  M                 +                              |  15        |
      Submucosa, Inflammation, Chronic     |             2                                                            |      4  2.0|
      Subserosa, Inflammation, Chronic     |                                                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  26                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 5| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 1| 7| 5| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 0| 6| 3| 3| 4| 2| 5| 3| 3| 3| 3| 3| 3| 3| 3| 2| 5| 3| 3| 4| 5| 5|             
                                           | 6| 6| 6| 0| 1| 7| 6| 4| 2| 7| 6| 6| 5| 5| 5| 7| 7| 5| 1| 7| 6| 6| 8| 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   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  A  +  M  +  +  A     +  +  +  +  M  +  +  +  M     +  +  +      |             
      Mucosa, Hyperplasia, Focal           |                                                    2                     |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +  +  +  +  +  A     +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  A  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  A  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  A  +  +  +  +  A     +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  A  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
      Amyloid Deposition                   |                                                    4                     |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A  +  +  +  +        +  +  +  +  +  +  +  +  A     +  +  +      |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Basophilic Focus                     |       X                                                                  |             
      Cyst                                 |                                                                          |             
      Eosinophilic Focus                   |                                     X                                    |             
      Focal Cellular Change                |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Inflammation, Chronic                |                                     1        1                           |             
      Necrosis                             |          4                                                               |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                        +                                 |             
      Fat, Necrosis, Focal                 |                                        3                                 |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  A  +  +  +  +  +     +  +  +  +  +  +  +  +  A     +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  M     +  +  +      |             
      Inflammation, Chronic                |    2  1     1  2  2           1     1  3  1     1  1           1  2      |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Tooth                                   |          +                                                               |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
      Coronary Artery, Inflammation,       |                                                                          |             
          Chronic                          |                                  4                                       |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Degeneration, Diffuse                |                                                                          |             
      Hematopoietic Cell Proliferation     |                      3                                            3      |             
      Hyperplasia, Focal                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  27                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 5| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 1| 7| 5| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 0| 6| 3| 3| 4| 2| 5| 3| 3| 3| 3| 3| 3| 3| 3| 2| 5| 3| 3| 4| 5| 5|             
                                           | 6| 6| 6| 0| 1| 7| 6| 4| 2| 7| 6| 6| 5| 5| 5| 7| 7| 5| 1| 7| 6| 6| 8| 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   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  M  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  A  +  +  +  +  +     +  +  +  +  +  +  +  +  M     +  +  +      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  M  M  +  +  M     +  +  +  M  +  +  +  +  +     +  +  M      |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia, Focal    | 2  4  2           3     2           3  3  3                              |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |       2        3                       2                       2         |             
      Follicle, Cyst                       |             X                                                            |             
      Follicular Cell, Hyperplasia         | 2  2  3  1        3  2  1     3  3  1  2  3  4  3  1  2        4         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |       +                                                                  |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  A  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Cyst                                 | X     X     X                                                     X      |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         |             2                                   2                 2      |             
      Serosa, Hyperplasia, Papillary       |                               2                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hydrometra                           |                                  3                                       |             
      Endometrium, Hyperplasia, Cystic     | 2  2  3        2  4     2     2        1  2  4  3  4                     |             
      Myometrium, Hyperplasia              |                                                                          |             
      Submucosa, Angiectasis               |                                     2                                    |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  A  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     M  +  +      |             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                   4      |             
      Mediastinal, Hyperplasia, Plasma Cell|                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +     M  +  +  +  +  +  +  +  +     M  +  +      |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Hyperplasia, Plasma Cell             |                                                                   4      |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  M  +  +     +  +  +  +  +  +  +  +  +     M  +  +      |             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid                |                                                 4                        |             
      Hyperplasia                          |                                              3                           |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Hematopoietic Cell Proliferation     | 4                                                                 4      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  28                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 5| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 1| 7| 5| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 0| 6| 3| 3| 4| 2| 5| 3| 3| 3| 3| 3| 3| 3| 3| 2| 5| 3| 3| 4| 5| 5|             
                                           | 6| 6| 6| 0| 1| 7| 6| 4| 2| 7| 6| 6| 5| 5| 5| 7| 7| 5| 1| 7| 6| 6| 8| 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   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Lymphoid                |             3                                                            |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  M  +  A     +  +  +  M  +  +  +  +  A     M  +  +      |             
      Ectopic Parathyroid Gland            | X                                               X                        |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  M  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hyperplasia                          |                                                                2         |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Ulcer                                |                      4                                            4      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Fibrous Osteodystrophy               |       1                             1                                    |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                         +                                                |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Atrophy                              |                                                                          |             
      Hemorrhage, Focal                    |          2                                                               |             
      Mineralization                       |       1                             1                             1      |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |          +  +                                                            |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Atelectasis                          |                                                                          |             
      Congestion                           |                                                             3            |             
      Inflammation, Chronic                | 1           2  1                                                  1      |             
      Metaplasia, Osseous                  |             2                                                            |             
      Alveolus, Hyperplasia, Macrophage    |                               3                                          |             
      Artery, Hypertrophy                  |                                                                          |             
      Artery, Capillary, Vein, Leukocytosis|                                                                          |             
      Peribronchiolar, Inflammation,       |                                                                          |             
          Chronic                          |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                        2     2                           |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Acute                  |                                                                          |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                               2        2                                 |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
      Conjunctiva, Retrobulbar,            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  29                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 5| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 1| 7| 5| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 0| 6| 3| 3| 4| 2| 5| 3| 3| 3| 3| 3| 3| 3| 3| 2| 5| 3| 3| 4| 5| 5|             
                                           | 6| 6| 6| 0| 1| 7| 6| 4| 2| 7| 6| 6| 5| 5| 5| 7| 7| 5| 1| 7| 6| 6| 8| 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   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7|             
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
          Inflammation                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                  +                                       |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Extraorbital, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                             4            |             
      Inflammation, Chronic                | 1  2  2     3     1           2  2  2  4  2  2  1  2              3      |             
      Metaplasia, Focal, Osseous           |             3                                                            |             
      Nephropathy                          |                                                                          |             
      Cortex, Fibrosis, Focal              |                                           3                              |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  A     +  +  +      |             
      Muscularis, Submucosa, Inflammation  |                                                                          |             
      Submucosa, Inflammation, Chronic,    |                                                                          |             
           Hemorrhagic                     |                                                                          |             
      Submucosa, Inflammation, Chronic     | 2  2  2     2     2           2  2  2  2  1  1     2           1  2      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  30                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 0| 0| 0| 0| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 7| 5| 5|             
                                           | 7| 7| 6| 6| 5| 5| 5| 5| 5| 4| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 7| 2| 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   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    100MG/KG                               | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +     +  +  +      |             
      Mucosa, Hyperplasia, Focal           |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  M  M  M  M  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  A      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Basophilic Focus                     |                                     X                                    |             
      Cyst                                 |          X                                                               |             
      Eosinophilic Focus                   |                                                                          |             
      Focal Cellular Change                |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Inflammation, Chronic                |                                     1              1           2         |             
      Necrosis                             |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                  +                             +         |             
      Fat, Necrosis, Focal                 |                                                                3         |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                                                             2            |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                | 2  2           1                 3  1  2     3  2  2  1     1  2         |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
      Coronary Artery, Inflammation,       |                                                                          |             
          Chronic                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Degeneration, Diffuse                |                4                                                         |             
      Hematopoietic Cell Proliferation     |                                                                   3      |             
      Hyperplasia, Focal                   |          2                                         3                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  31                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 0| 0| 0| 0| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 7| 5| 5|             
                                           | 7| 7| 6| 6| 5| 5| 5| 5| 5| 4| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 7| 2| 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   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    100MG/KG                               | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  M  M  M  M  +  +  +  +  +  +  +  +  +  +  +     M  +  +      |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +     +  +  +      |             
      Pars Distalis, Angiectasis           |                                              1                           |             
      Pars Distalis, Hyperplasia, Focal    |                                  2        3                    2         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Chronic                |                               2                       2                  |             
      Follicle, Cyst                       |                                                                          |             
      Follicular Cell, Hyperplasia         | 4  2  3  2  3  4              4  3  3  1  1  3  3  3  2     3  2  3      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |             +                                                            |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Cyst                                 |    X     X  X                 X     X     X  X     X                     |             
      Periovarian Tissue, Inflammation,    |                                                                          |             
           Chronic                         | 3                                                                        |             
      Serosa, Hyperplasia, Papillary       |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hydrometra                           |             4                                                            |             
      Endometrium, Hyperplasia, Cystic     | 3  3  3  2     3              4  3  2        4  2  3  2     2  3         |             
      Myometrium, Hyperplasia              |                                                                          |             
      Submucosa, Angiectasis               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hyperplasia, Plasma Cell             |          4                                                               |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
      Mediastinal, Hyperplasia, Plasma Cell|                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +     M  +  M  +  +  +  +  +  +  +  M  +  +  +  +     +  +  +      |             
      Hyperplasia, Lymphoid                | 4                                                                        |             
      Hyperplasia, Plasma Cell             |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Congestion                           |                                                             3            |             
      Hyperplasia, Lymphoid                | 3                                                                        |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  32                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 0| 0| 0| 0| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 7| 5| 5|             
                                           | 7| 7| 6| 6| 5| 5| 5| 5| 5| 4| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 7| 2| 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   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    100MG/KG                               | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +     +  +  M      |             
      Ectopic Parathyroid Gland            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Hyperplasia                          |                               1                 1           2            |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Fibrous Osteodystrophy               |                                                       2                  |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Atrophy                              |                                                 3                        |             
      Hemorrhage, Focal                    |                                                                          |             
      Mineralization                       |                                                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Atelectasis                          |                                                                          |             
      Congestion                           |                   3        3                                             |             
      Inflammation, Chronic                |                                           2                              |             
      Metaplasia, Osseous                  |                                                                          |             
      Alveolus, Hyperplasia, Macrophage    |                                                    3                     |             
      Artery, Hypertrophy                  |                                                       3                  |             
      Artery, Capillary, Vein, Leukocytosis|                                                                          |             
      Peribronchiolar, Inflammation,       |                                                                          |             
          Chronic                          |                                                                          |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Inflammation, Acute                  |                      2                                                   |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |          +                          +              +                     |             
      Conjunctiva, Retrobulbar,            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  33                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 0| 0| 0| 0| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 7| 5| 5|             
                                           | 7| 7| 6| 6| 5| 5| 5| 5| 5| 4| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 7| 2| 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   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    100MG/KG                               | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
          Inflammation                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         | +     +  +                          +              +                     |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                                 +                        |             
      Inflammation, Chronic                |                                                 2                        |             
      Extraorbital, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Inflammation, Chronic                | 3  2     1     1                    2  1  2  2  1     1     1            |             
      Metaplasia, Focal, Osseous           |                                                                          |             
      Nephropathy                          |                                        3                                 |             
      Cortex, Fibrosis, Focal              |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +      |             
      Muscularis, Submucosa, Inflammation  |                                                                          |             
      Submucosa, Inflammation, Chronic,    |                                                                          |             
           Hemorrhagic                     |                                        3                                 |             
      Submucosa, Inflammation, Chronic     | 3  2  2  2  2  2              2  2        2  1     2  2     1  2         |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  34                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 4| 7| 7| 7| 6| 4| 7| 7| 6| 4| 3|                             |            |
                             DAY ON TEST   | 3| 3| 3| 5| 5| 3| 3| 3| 8| 5| 2| 0| 4| 5| 8|                             |            |
                                           | 7| 6| 6| 2| 7| 7| 7| 5| 6| 7| 9| 2| 1| 7| 9|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|                             |      A     |
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +     +  +  M  +     +  +  +     +                              |  48        |
      Mucosa, Hyperplasia, Focal           |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Intestine Large                         | +  +  +  +     +  +  +  +     +  +  +     +                              |  53        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  53        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +     +  +  +  +     +  +  +     +                              |  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         | +  +  +  +     +  +  +  +     +  +  +     +                              |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +     +  +  +  +     +  +  +     +                              |  51        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  52        |
      Amyloid Deposition                   |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +     +  +  +  +     +  +  +     +                              |  52        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Amyloid Deposition                   |          4                                                               |      1  4.0|
      Basophilic Focus                     |       X                                                                  |      3     |
      Cyst                                 |                                                                          |      1     |
      Eosinophilic Focus                   |       X                                                                  |      2     |
      Focal Cellular Change                |                                  X                                       |      1     |
      Hematopoietic Cell Proliferation     |          4                                                               |      1  4.0|
      Inflammation, Chronic                |                                                                          |      5  1.2|
      Necrosis                             |                                  3                                       |      2  3.5|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                     +                                    |   4        |
      Fat, Necrosis, Focal                 |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +     +  +  +  +     +  +  +     +                              |  53        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +     +  +  +  +     +  +  +     +                              |  54        |
      Inflammation, Chronic                | 1  2  2        2  2  2  1                 2                              |     33  1.7|
                                            __________________________________________________________________________|____________|
   Stomach                                 | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Inflammation, Chronic                |                               3                                          |      1  3.0|
      Coronary Artery, Inflammation,       |                                                                          |            |
          Chronic                          |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  35                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 4| 7| 7| 7| 6| 4| 7| 7| 6| 4| 3|                             |            |
                             DAY ON TEST   | 3| 3| 3| 5| 5| 3| 3| 3| 8| 5| 2| 0| 4| 5| 8|                             |            |
                                           | 7| 6| 6| 2| 7| 7| 7| 5| 6| 7| 9| 2| 1| 7| 9|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|                             |      A     |
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Degeneration, Diffuse                |                                                                          |      1  4.0|
      Hematopoietic Cell Proliferation     |          4                                                               |      4  3.3|
      Hyperplasia, Focal                   |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  | +  +  +  M     +  +  +  +     +  +  +     +                              |  52        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +     +  +  +  +     +  M  +     +                              |  52        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  M     +  +  +  +     M  +  +     +                              |  40        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +     +  +  M  +     +  +  +     +                              |  52        |
      Pars Distalis, Angiectasis           | 2  4  4                                                                  |      4  2.8|
      Pars Distalis, Hyperplasia, Focal    |                         2           2                                    |     13  2.5|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Inflammation, Chronic                | 2                 2           2                                          |      9  2.1|
      Follicle, Cyst                       |                                                                          |      1     |
      Follicular Cell, Hyperplasia         | 3  2  3        3  3  3  1     4  2  2                                    |     45  2.6|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +     +  +  +  +     +  +  +     +                              |  54        |
      Cyst                                 |    X                          X                                          |     14     |
      Periovarian Tissue, Inflammation,    |                                                                          |            |
           Chronic                         |                                                                          |      4  2.3|
      Serosa, Hyperplasia, Papillary       |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Hydrometra                           |                                                                          |      2  3.5|
      Endometrium, Hyperplasia, Cystic     | 4  2           2  3  2                                                   |     31  2.7|
      Myometrium, Hyperplasia              |                                     2                                    |      1  2.0|
      Submucosa, Angiectasis               |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +     +  +  +  +     +  +  +     +                              |  54        |
      Hyperplasia                          |          4                                                               |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +  +  +  +     +  +  +  +     +  +  +     +                              |  54        |
      Hyperplasia, Plasma Cell             |                                                                          |      1  4.0|
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |      1  4.0|
      Mediastinal, Hyperplasia, Plasma Cell|                                     4                                    |      1  4.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  36                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 4| 7| 7| 7| 6| 4| 7| 7| 6| 4| 3|                             |            |
                             DAY ON TEST   | 3| 3| 3| 5| 5| 3| 3| 3| 8| 5| 2| 0| 4| 5| 8|                             |            |
                                           | 7| 6| 6| 2| 7| 7| 7| 5| 6| 7| 9| 2| 1| 7| 9|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|                             |      A     |
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  49        |
      Hyperplasia, Lymphoid                |                                                                          |      1  4.0|
      Hyperplasia, Plasma Cell             |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  52        |
      Congestion                           |                               4                                          |      2  3.5|
      Hyperplasia, Lymphoid                |                                                                          |      2  3.5|
      Hyperplasia                          |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Amyloid Deposition                   |          2                                                               |      1  2.0|
      Hematopoietic Cell Proliferation     |          4     4                                                         |      4  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +     +  +  +  +     +  +  +     M                              |  47        |
      Ectopic Parathyroid Gland            |                                                                          |      2     |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +     +  +  +  +     +  +  +     +                              |  53        |
      Hyperplasia                          |       2                                                                  |      5  1.6|
      Inflammation, Chronic                |                                     2                                    |      1  2.0|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Ulcer                                |                                  3  4                                    |      4  3.8|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Fibrous Osteodystrophy               |                                                                          |      3  1.3|
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Atrophy                              |                                                                          |      1  3.0|
      Hemorrhage, Focal                    |                                                                          |      1  2.0|
      Mineralization                       |                                                                          |      3  1.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                           +                              |   3        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Atelectasis                          |    3                                                                     |      1  3.0|
      Congestion                           |                                                                          |      3  3.0|
      Inflammation, Chronic                |                                                                          |      5  1.4|
      Metaplasia, Osseous                  |                                                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  37                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 4| 7| 7| 7| 6| 4| 7| 7| 6| 4| 3|                             |            |
                             DAY ON TEST   | 3| 3| 3| 5| 5| 3| 3| 3| 8| 5| 2| 0| 4| 5| 8|                             |            |
                                           | 7| 6| 6| 2| 7| 7| 7| 5| 6| 7| 9| 2| 1| 7| 9|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|                             |      A     |
    100MG/KG                               | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Alveolus, Hyperplasia, Macrophage    |                                                                          |      2  3.0|
      Artery, Hypertrophy                  |                                                                          |      1  3.0|
      Artery, Capillary, Vein, Leukocytosis|          X                                                               |      1     |
      Peribronchiolar, Inflammation,       |                                                                          |            |
          Chronic                          |                      2                                                   |      1  2.0|
      Perivascular, Inflammation, Chronic  |                                                                          |      2  2.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Inflammation, Acute                  |                                                                          |      1  2.0|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic                         |                                                                          |      2  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                     +     +                              |   5        |
      Conjunctiva, Retrobulbar,            |                                                                          |            |
          Inflammation                     |                                     3                                    |      1  3.0|
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                     +                                    |   7        |
                                            __________________________________________________________________________|____________|
   Lacrimal Gland                          |       +                                                                  |   2        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Extraorbital, Inflammation, Chronic  |       2                                                                  |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +     +  +  +  +     +  +  +     +                              |  55        |
      Amyloid Deposition                   |          4                                                               |      2  4.0|
      Inflammation, Chronic                |    2  1  2     1  2  2  1     2           2                              |     34  1.8|
      Metaplasia, Focal, Osseous           |                                                                          |      1  3.0|
      Nephropathy                          |                                                                          |      1  3.0|
      Cortex, Fibrosis, Focal              |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +     +  +  +  +     +  +  +     +                              |  54        |
      Muscularis, Submucosa, Inflammation  |          2                                                               |      1  2.0|
      Submucosa, Inflammation, Chronic,    |                                                                          |            |
           Hemorrhagic                     |                                                                          |      1  3.0|
      Submucosa, Inflammation, Chronic     | 1  1  2           2  2                                                   |     33  1.8|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  38                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 4| 3| 7| 7| 6| 6| 6| 7| 7| 7| 6| 5| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 2| 9| 8| 2| 3| 3| 2| 5| 4| 3| 3| 9| 9| 0| 3| 2| 2| 8| 5| 3| 2| 2| 5| 0|             
                                           | 0| 9| 1| 3| 1| 0| 0| 9| 8| 7| 1| 0| 8| 4| 5| 0| 9| 9| 2| 5| 1| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  A  +  +  +     A  +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +  +  +  +  +     A  +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +        +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +        +  +  +  +  A  +  M  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +        +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  +  +  +  +  +     A  +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +        +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +        +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
      Amyloid Deposition                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +        +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Basophilic Focus                     |    X                             X                                       |             
      Cyst                                 |                                     X                                    |             
      Eosinophilic Focus                   |                                     X                                    |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Infarct                              |                                                                          |             
      Mixed Cell Focus                     |                X  X                                                      |             
      Necrosis, Focal                      |                                              2                           |             
      Necrosis                             |                                                                          |             
      Syncytial Alteration                 |             1                    1                       1              1|             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                            +        +  +                                 |             
      Hemorrhage                           |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
      Fat, Necrosis, Focal                 |                                        4                                 |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Fibrosis, Focal                      |                                                                          |             
      Hemorrhage, Focal                    |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Degeneration, Chronic                |    2                                                                     |             
      Inflammation, Chronic                |       2  1        1              2  1  1     2  2     1     1  2  1      |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Ulcer                                |                                                          3               |             
                                            __________________________________________________________________________|             
   Tooth                                   |                      +        +                                +         |             
      Peridontal Tissue, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                          |             
      Peridontal Tissue, Pulp, Abscess     |                      4                                                   |             
      Pulp, Abscess                        |                               4                                          |             
      Pulp, Necrosis                       |                                                                3         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  39                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 4| 3| 7| 7| 6| 6| 6| 7| 7| 7| 6| 5| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 2| 9| 8| 2| 3| 3| 2| 5| 4| 3| 3| 9| 9| 0| 3| 2| 2| 8| 5| 3| 2| 2| 5| 0|             
                                           | 0| 9| 1| 3| 1| 0| 0| 9| 8| 7| 1| 0| 8| 4| 5| 0| 9| 9| 2| 5| 1| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Inflammation, Acute                  |          3                                                               |             
      Inflammation, Chronic                |                                        1                                 |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Subcapsular, Hyperplasia             |                                                          3               |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Degeneration, Focal                  |    4           3                                                         |             
      Ectopic Tissue                       |                                                             X            |             
      Hyperplasia, Focal                   |                   3  3           2                 2              1      |             
      Hypertrophy, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Hyperplasia, Focal                   |                                                 2                        |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  +  +  +  M  +     +  M  +  +  +  +  +  +  M  +  +  +  M  +     M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Pars Distalis, Hyperplasia, Focal    |       2                                            2           2         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Follicle, Cyst, Multiple             |                                                                          |             
      Follicular Cell, Hyperplasia         |                                                 1                 1      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Inflammation, Chronic                |                                                       3                  |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +              +           +                                   +        +|             
      Inflammation, Chronic                |                            2                                             |             
      Inflammation, Suppurative            |                4                                                        4|             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Inflammation, Chronic                |                            2                                             |             
      Inflammation, Chronic Active         |                                                       4                  |             
      Inflammation, Suppurative            |             4                                                            |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Dilatation                           |                                                             4            |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |             4                                                            |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Atrophy                              |                2                                                         |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  40                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 4| 3| 7| 7| 6| 6| 6| 7| 7| 7| 6| 5| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 2| 9| 8| 2| 3| 3| 2| 5| 4| 3| 3| 9| 9| 0| 3| 2| 2| 8| 5| 3| 2| 2| 5| 0|             
                                           | 0| 9| 1| 3| 1| 0| 0| 9| 8| 7| 1| 0| 8| 4| 5| 0| 9| 9| 2| 5| 1| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Axillary, Hyperplasia, Lymphoid      |                                                          4               |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
      Iliac, Hyperplasia, Lymphoid         |                                                          4               |             
      Iliac, Hyperplasia, Plasma Cell      |                                                                          |             
      Inguinal, Cyst                       |                                                                          |             
      Lumbar, Congestion                   |                                        3                                 |             
      Lumbar, Hyperplasia, Lymphoid        |                                                          4               |             
      Mediastinal, Hyperplasia             |                                        3                                 |             
      Pancreatic, Congestion               |                                                                          |             
      Popliteal, Hyperplasia, Lymphoid     |                                                          4               |             
      Popliteal, Hyperplasia, Plasma Cell  |                                                                          |             
      Renal, Hyperplasia, Lymphoid         |                                                                          |             
      Renal, Hyperplasia, Plasma Cell      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +     M  +  +  +  +  +  +  +  +  +  +  +  M  +     M|             
      Congestion                           |          2                                                               |             
      Hyperplasia, Lymphoid                |                                                          4               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Congestion                           |          4                             3              4                  |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                    4     4               |             
      Inflammation, Acute                  |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Hematopoietic Cell Proliferation     |                                           4           4  4               |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  M  +  +  +  +     +  +  +  M  +  M  +  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|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Acanthosis                           |                                                       3                  |             
      Atrophy                              |                                                                          |             
      Inflammation, Chronic                |                3                                                         |             
      Ulcer                                |       4                                   1              4               |             
      Artery, Subcutaneous Tissue,         |                                                                          |             
          Inflammation, Chronic            |                                                 4                        |             
      Dermis, Fibrosis                     |                                              4                           |             
      Dermis, Inflammation, Chronic        |                                              2                           |             
      Prepuce, Inflammation, Chronic       |                                                                          |             
      Subcutaneous Tissue, Edema           |                                                                          |             
      Subcutaneous Tissue, Hemorrhage      |          4                                                               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  41                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 4| 3| 7| 7| 6| 6| 6| 7| 7| 7| 6| 5| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 2| 9| 8| 2| 3| 3| 2| 5| 4| 3| 3| 9| 9| 0| 3| 2| 2| 8| 5| 3| 2| 2| 5| 0|             
                                           | 0| 9| 1| 3| 1| 0| 0| 9| 8| 7| 1| 0| 8| 4| 5| 0| 9| 9| 2| 5| 1| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Chronic                         |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Subacute                        |          3                                                               |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                                                                         4|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +     +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Joint, Tarsal, Hyperostosis          |       X                                   X     X                        |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                     +                                    |             
      Abdominal, Fibrosis                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Mineralization                       |                1                                                         |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                   +                    +                                 |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Alveolus, Hyperplasia, Macrophage    |       3                                                                  |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Lumen, Turbinate, Inflammation,      |                                                                          |             
          Suppurative                      | 2                                                                        |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |       3                             2                                    |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |             +                                +                           |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |       +                                      +                           |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +     +|             
      Calculus Micro Observation Only      |                                                                         X|             
      Cyst, Multiple                       |                                                                          |             
      Glomerulosclerosis                   |       3                                         3     4                  |             
      Inflammation, Chronic                | 1  1     2  3  2  1           2  2  2  3  3  2  2  1  3  2  1  2  1      |             
      Inflammation, Suppurative            |                                                                          |             
      Nephropathy                          |                                                                          |             
      Cortex, Infarct                      |          4                                                               |             
                                            __________________________________________________________________________|             
   Urethra                                 |                                                                         +|             
      Distal, Inflammation, Chronic        |                                                                          |             
      Proximal, Inflammation, Suppurative  |                                                                         4|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  42                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 4| 3| 7| 7| 6| 6| 6| 7| 7| 7| 6| 5| 7| 7| 7| 4| 4|             
                             DAY ON TEST   | 3| 2| 9| 8| 2| 3| 3| 2| 5| 4| 3| 3| 9| 9| 0| 3| 2| 2| 8| 5| 3| 2| 2| 5| 0|             
                                           | 0| 9| 1| 3| 1| 0| 0| 9| 8| 7| 1| 0| 8| 4| 5| 0| 9| 9| 2| 5| 1| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +     +  +  +  +  +  A  +  +  +  +  +  +  +  +     +|             
      Perivascular, Inflammation, Chronic  |                                                          2               |             
      Submucosa, Inflammation, Chronic     |       1                          2           2  2     3           1      |             
      Wall, Inflammation, Subacute         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  43                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 4| 7| 7| 6| 4| 4| 7| 7| 7| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 4|             
                             DAY ON TEST   | 3| 3| 2| 3| 5| 3| 3| 8| 5| 5| 2| 2| 2| 5| 5| 3| 2| 0| 3| 5| 3| 3| 2| 8| 5|             
                                           | 1| 0| 9| 0| 8| 1| 0| 4| 8| 8| 9| 9| 9| 8| 8| 1| 9| 1| 5| 8| 1| 1| 9| 1| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 1| 1| 1| 1| 1|             
    VEHICLE                                | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  A     +  +  A        +  +  +        +  +  +  +     +  +  +  M   |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  A     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +        +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +        +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +        +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  A     +  +  A        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +        +  +           +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +        +  +           +  +  +        +  +  +  +     +  +  +  +   |             
      Amyloid Deposition                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +        +  +           +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Basophilic Focus                     |                                                                          |             
      Cyst                                 |                                                                          |             
      Eosinophilic Focus                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Infarct                              |                                                                          |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis, Focal                      |                                                                          |             
      Necrosis                             |          4                                                               |             
      Syncytial Alteration                 |    1                                                                     |             
      Thrombosis                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |       +                                                              +   |             
      Hemorrhage                           |       3                                                                  |             
      Inflammation, Acute                  |                                                                      4   |             
      Fat, Necrosis, Focal                 |                                                                      4   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Fibrosis, Focal                      |                               3                                          |             
      Hemorrhage, Focal                    |                               3                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Degeneration, Chronic                |                                                                          |             
      Inflammation, Chronic                | 1  2  2        2     2        2  1  2        2     1        1            |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Tooth                                   | +                 +                          +                           |             
      Peridontal Tissue, Inflammation,     |                                                                          |             
           Suppurative                     |                   4                          3                           |             
      Peridontal Tissue, Pulp, Abscess     |                                                                          |             
      Pulp, Abscess                        | 3                                                                        |             
      Pulp, Necrosis                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  44                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 4| 7| 7| 6| 4| 4| 7| 7| 7| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 4|             
                             DAY ON TEST   | 3| 3| 2| 3| 5| 3| 3| 8| 5| 5| 2| 2| 2| 5| 5| 3| 2| 0| 3| 5| 3| 3| 2| 8| 5|             
                                           | 1| 0| 9| 0| 8| 1| 0| 4| 8| 8| 9| 9| 9| 8| 8| 1| 9| 1| 5| 8| 1| 1| 9| 1| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 1| 1| 1| 1| 1|             
    VEHICLE                                | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Subcapsular, Hyperplasia             |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Degeneration, Focal                  |                                  2                                       |             
      Ectopic Tissue                       |                                                                          |             
      Hyperplasia, Focal                   |                4                             2                           |             
      Hypertrophy, Focal                   |                                  2                                       |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +     +  +  +        +  M  +        +  +  +  +     +  +  +  +   |             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +     +  +  +        +  +  +        M  M  +  +     +  +  M  M   |             
      Pars Distalis, Hyperplasia, Focal    |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Follicle, Cyst, Multiple             |       X                                                                  |             
      Follicular Cell, Hyperplasia         |                1                                                         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                +         |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |       +           +              +  +                 +                  |             
      Inflammation, Chronic                |       3           4              3  4                                    |             
      Inflammation, Suppurative            |                   4                                   4                  |             
      Duct, Ectasia                        |                                  3                                       |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Inflammation, Chronic                | 1                             2     2                          4         |             
      Inflammation, Chronic Active         |                                                                      3   |             
      Inflammation, Suppurative            |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Dilatation                           |                                                                          |             
      Inflammation, Chronic                |                                                                3         |             
      Inflammation, Suppurative            |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Atrophy                              |                                                    3                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  45                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 4| 7| 7| 6| 4| 4| 7| 7| 7| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 4|             
                             DAY ON TEST   | 3| 3| 2| 3| 5| 3| 3| 8| 5| 5| 2| 2| 2| 5| 5| 3| 2| 0| 3| 5| 3| 3| 2| 8| 5|             
                                           | 1| 0| 9| 0| 8| 1| 0| 4| 8| 8| 9| 9| 9| 8| 8| 1| 9| 1| 5| 8| 1| 1| 9| 1| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 1| 1| 1| 1| 1|             
    VEHICLE                                | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Axillary, Hyperplasia, Lymphoid      |                                                                          |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
      Iliac, Hyperplasia, Lymphoid         |                                                                          |             
      Iliac, Hyperplasia, Plasma Cell      |                                                                          |             
      Inguinal, Cyst                       |                                                       X                  |             
      Lumbar, Congestion                   |                                                                          |             
      Lumbar, Hyperplasia, Lymphoid        |                                                                          |             
      Mediastinal, Hyperplasia             |                                                                          |             
      Pancreatic, Congestion               |                      4                                                   |             
      Popliteal, Hyperplasia, Lymphoid     |                                                                          |             
      Popliteal, Hyperplasia, Plasma Cell  |                                                                          |             
      Renal, Hyperplasia, Lymphoid         |                                                                3         |             
      Renal, Hyperplasia, Plasma Cell      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Congestion                           |                      4                                4        3         |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Hematopoietic Cell Proliferation     |          4                                         4  4              4   |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  M     +  +  M        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   |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Acanthosis                           |                      3                                                   |             
      Atrophy                              |          3                                                               |             
      Inflammation, Chronic                |                                                                          |             
      Ulcer                                |          2                                            4                  |             
      Artery, Subcutaneous Tissue,         |                                                                          |             
          Inflammation, Chronic            |                                                                          |             
      Dermis, Fibrosis                     |                                                                          |             
      Dermis, Inflammation, Chronic        |                                                                          |             
      Prepuce, Inflammation, Chronic       |                                                       4                  |             
      Subcutaneous Tissue, Edema           |          4                                                               |             
      Subcutaneous Tissue, Hemorrhage      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  46                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 4| 7| 7| 6| 4| 4| 7| 7| 7| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 4|             
                             DAY ON TEST   | 3| 3| 2| 3| 5| 3| 3| 8| 5| 5| 2| 2| 2| 5| 5| 3| 2| 0| 3| 5| 3| 3| 2| 8| 5|             
                                           | 1| 0| 9| 0| 8| 1| 0| 4| 8| 8| 9| 9| 9| 8| 8| 1| 9| 1| 5| 8| 1| 1| 9| 1| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 1| 1| 1| 1| 1|             
    VEHICLE                                | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Chronic                         |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Subacute                        |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Joint, Tarsal, Hyperostosis          |          X        X              X                          X  X  X      |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |          +                                                               |             
      Abdominal, Fibrosis                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Mineralization                       |                                  1                                       |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |          +                                                               |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Alveolus, Hyperplasia, Macrophage    |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Lumen, Turbinate, Inflammation,      |                                                                          |             
          Suppurative                      |                                                                1         |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                       +                  |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                       +                  |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Calculus Micro Observation Only      |                      X                                                   |             
      Cyst, Multiple                       |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Inflammation, Chronic                | 1  2  1  1     1  1           2     1        2  2  2        2            |             
      Inflammation, Suppurative            |                                                                      4   |             
      Nephropathy                          |                                                                4         |             
      Cortex, Infarct                      |                                                                          |             
                                            __________________________________________________________________________|             
   Urethra                                 |                                                                +         |             
      Distal, Inflammation, Chronic        |                                                                3         |             
      Proximal, Inflammation, Suppurative  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  47                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 4| 7| 7| 6| 4| 4| 7| 7| 7| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 4|             
                             DAY ON TEST   | 3| 3| 2| 3| 5| 3| 3| 8| 5| 5| 2| 2| 2| 5| 5| 3| 2| 0| 3| 5| 3| 3| 2| 8| 5|             
                                           | 1| 0| 9| 0| 8| 1| 0| 4| 8| 8| 9| 9| 9| 8| 8| 1| 9| 1| 5| 8| 1| 1| 9| 1| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 1| 1| 1| 1| 1|             
    VEHICLE                                | 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0|             
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +     +  +  +        +  +  +        +  +  +  +     +  +  +  +   |             
      Perivascular, Inflammation, Chronic  |                                                                          |             
      Submucosa, Inflammation, Chronic     |    1           1     1                                1     1  4         |             
      Wall, Inflammation, Subacute         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  48                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 6| 5| 7| 7| 7| 6| 3|                             |            |
                             DAY ON TEST   | 3| 0| 4| 4| 5| 3| 3| 2| 6| 3| 3| 3| 2| 0| 3|                             |            |
                                           | 0| 9| 9| 8| 8| 1| 0| 9| 2| 7| 1| 0| 9| 4| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  A  +     M  +  +  +  M  +  +  +  A  A                              |  44        |
                                            __________________________________________________________________________|____________|
   Intestine Large                         | +  +  A  A     +  +  +  +  +  +  +  +  +  +                              |  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +           +  +  +  +  +  +  +  +  A  +                              |  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +           +  +  +  +  +  +  +  +  +  +                              |  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +           +  +  +  +  +  +  +  +  +  +                              |  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         | +  +  A  +     +  +  +  +  +  +  +  +  +  +                              |  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +     +     +  +  +  +  +  +  +  +  +  +                              |  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +     A     +  +  +  +  +  +  +  +  A  +                              |  48        |
      Amyloid Deposition                   | 4                                                                        |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +     +     +  +  +  +  +  +  +  +  +  +                              |  50        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Basophilic Focus                     |                                                                          |      2     |
      Cyst                                 |                                                                          |      1     |
      Eosinophilic Focus                   |                               X                                          |      2     |
      Hematopoietic Cell Proliferation     |    4                                                                     |      1  4.0|
      Infarct                              |                   4                                                      |      1  4.0|
      Mixed Cell Focus                     |                                                                          |      2     |
      Necrosis, Focal                      |                                                                          |      1  2.0|
      Necrosis                             |    4     4                             4                                 |      4  4.0|
      Syncytial Alteration                 |                                                                          |      5  1.0|
      Thrombosis                           |                                        4                                 |      1  4.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |    +                                                                     |   6        |
      Hemorrhage                           |                                                                          |      1  3.0|
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Fat, Necrosis, Focal                 |    4                                                                     |      3  4.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  A  +     +  +  +  +  +  +  +  +  +  +                              |  54        |
      Fibrosis, Focal                      |                                                                          |      1  3.0|
      Hemorrhage, Focal                    |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Degeneration, Chronic                |                                                                          |      1  2.0|
      Inflammation, Chronic                | 1  2  1        1  1  2        2                                          |     30  1.5|
                                            __________________________________________________________________________|____________|
   Stomach                                 | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Ulcer                                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   6        |
      Peridontal Tissue, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      2  3.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  49                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 6| 5| 7| 7| 7| 6| 3|                             |            |
                             DAY ON TEST   | 3| 0| 4| 4| 5| 3| 3| 2| 6| 3| 3| 3| 2| 0| 3|                             |            |
                                           | 0| 9| 9| 8| 8| 1| 0| 9| 2| 7| 1| 0| 9| 4| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Peridontal Tissue, Pulp, Abscess     |                                                                          |      1  4.0|
      Pulp, Abscess                        |                                                                          |      2  3.5|
      Pulp, Necrosis                       |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Inflammation, Acute                  |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Subcapsular, Hyperplasia             |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Degeneration, Focal                  |                2     3                                                   |      5  2.8|
      Ectopic Tissue                       |                                                                          |      1     |
      Hyperplasia, Focal                   |                               3     3                                    |      9  2.6|
      Hypertrophy, Focal                   |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  54        |
      Hyperplasia, Focal                   |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  A  +     +  +  +  +  +  +  M  +  +  +                              |  53        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +     M  +  M  +  +  +  M  +  +  +                              |  46        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +     +  +  +  +  +  +  +  +  +  M                              |  50        |
      Pars Distalis, Hyperplasia, Focal    |                                                                          |      3  2.0|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Follicle, Cyst, Multiple             |                                                                          |      1     |
      Follicular Cell, Hyperplasia         |                               1  2                                       |      5  1.2|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Coagulating Gland                       |                +                                                         |   1        |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +     +  +  M  +  +  +  +  +  +  +                              |  54        |
      Inflammation, Chronic                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Penis                                   |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         |                                     +                                    |  11        |
      Inflammation, Chronic                |                                                                          |      5  3.2|
      Inflammation, Suppurative            |                                     4                                    |      5  4.0|
      Duct, Ectasia                        |                                                                          |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  50                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 6| 5| 7| 7| 7| 6| 3|                             |            |
                             DAY ON TEST   | 3| 0| 4| 4| 5| 3| 3| 2| 6| 3| 3| 3| 2| 0| 3|                             |            |
                                           | 0| 9| 9| 8| 8| 1| 0| 9| 2| 7| 1| 0| 9| 4| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Inflammation, Chronic                |                4                                                         |      6  2.5|
      Inflammation, Chronic Active         |                         3                                                |      3  3.3|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Dilatation                           |                                                                          |      1  4.0|
      Inflammation, Chronic                |                4                                                         |      2  3.5|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Atrophy                              |                                                                          |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Hyperplasia, Plasma Cell             |                4                                                         |      1  4.0|
      Axillary, Hyperplasia, Lymphoid      |                                                                          |      1  4.0|
      Axillary, Hyperplasia, Plasma Cell   |                         4                                                |      1  4.0|
      Iliac, Hyperplasia, Lymphoid         |                                                                          |      1  4.0|
      Iliac, Hyperplasia, Plasma Cell      |                         4                                                |      1  4.0|
      Inguinal, Cyst                       |                                                                          |      1     |
      Lumbar, Congestion                   |                                                                          |      1  3.0|
      Lumbar, Hyperplasia, Lymphoid        |                                                                          |      1  4.0|
      Mediastinal, Hyperplasia             |                                                                          |      1  3.0|
      Pancreatic, Congestion               |                                                                          |      1  4.0|
      Popliteal, Hyperplasia, Lymphoid     |                                                                          |      1  4.0|
      Popliteal, Hyperplasia, Plasma Cell  |                         4                                                |      1  4.0|
      Renal, Hyperplasia, Lymphoid         |                                                                          |      1  3.0|
      Renal, Hyperplasia, Plasma Cell      |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  52        |
      Congestion                           |                                     3                                    |      2  2.5|
      Hyperplasia, Lymphoid                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +     M  +  +  +  +  +  +  +  +  +                              |  54        |
      Congestion                           | 4        4                 4        3  3                                 |     11  3.6|
      Hematopoietic Cell Proliferation     |    4                                                                     |      1  4.0|
      Hyperplasia, Lymphoid                |                                     4                                    |      3  4.0|
      Inflammation, Acute                  |          4                                                               |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Hematopoietic Cell Proliferation     |    4     4              4                                                |     10  4.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  M     +  +  +  +  M  +  +  +  M  +                              |  39        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  51                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 6| 5| 7| 7| 7| 6| 3|                             |            |
                             DAY ON TEST   | 3| 0| 4| 4| 5| 3| 3| 2| 6| 3| 3| 3| 2| 0| 3|                             |            |
                                           | 0| 9| 9| 8| 8| 1| 0| 9| 2| 7| 1| 0| 9| 4| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M     M  M  M  M  M  M  M  M  M  M                              |   1        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Acanthosis                           |                                                                          |      2  3.0|
      Atrophy                              |                            2                                             |      2  2.5|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Ulcer                                |                                                                          |      5  3.0|
      Artery, Subcutaneous Tissue,         |                                                                          |            |
          Inflammation, Chronic            |                                                                          |      1  4.0|
      Dermis, Fibrosis                     |                                                                          |      1  4.0|
      Dermis, Inflammation, Chronic        |                                                                          |      1  2.0|
      Prepuce, Inflammation, Chronic       |                            2                                             |      2  3.0|
      Subcutaneous Tissue, Edema           |                                        4                                 |      2  4.0|
      Subcutaneous Tissue, Hemorrhage      |                                                                          |      1  4.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Chronic                         |                         2                                                |      1  2.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Subacute                        |                                                                          |      1  3.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Suppurative                     |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  54        |
      Joint, Tarsal, Hyperostosis          |                                  X                                       |     10     |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |    +                                                                     |   3        |
      Abdominal, Fibrosis                  |    3                                                                     |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Mineralization                       |                                                                          |      2  1.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                                                          |   3        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Alveolus, Hyperplasia, Macrophage    |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Lumen, Turbinate, Inflammation,      |                                                                          |            |
          Suppurative                      |                                                                          |      2  1.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  52                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 4| 7| 7| 7| 6| 5| 7| 7| 7| 6| 3|                             |            |
                             DAY ON TEST   | 3| 0| 4| 4| 5| 3| 3| 2| 6| 3| 3| 3| 2| 0| 3|                             |            |
                                           | 0| 9| 9| 8| 8| 1| 0| 9| 2| 7| 1| 0| 9| 4| 0|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    VEHICLE                                | 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|                             |      L     |
    CONTROL                                | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic                         |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   3        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         | +     +                                                                  |   5        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  55        |
      Calculus Micro Observation Only      |                                                                          |      2     |
      Cyst, Multiple                       |                X                                                         |      1     |
      Glomerulosclerosis                   |                                                                          |      3  3.3|
      Inflammation, Chronic                | 2  2  2  1     3  2  2  4  3  2  2  2  1  1                              |     45  1.8|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
      Nephropathy                          |                                                                          |      1  4.0|
      Cortex, Infarct                      |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Urethra                                 |                +                                                         |   3        |
      Distal, Inflammation, Chronic        |                                                                          |      1  3.0|
      Proximal, Inflammation, Suppurative  |                4                                                         |      2  4.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +     +  +  +  +  +  +  +  +  +  +                              |  54        |
      Perivascular, Inflammation, Chronic  |                            3                                             |      2  2.5|
      Submucosa, Inflammation, Chronic     |                   2           1  1                                       |     15  1.6|
      Wall, Inflammation, Subacute         |                4                                                         |      1  4.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  53                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 4| 4| 2| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 0| 5| 5| 6| 3| 3| 3| 3| 5| 3| 3| 5| 5| 1| 3| 2| 8| 4| 6| 3| 3| 3| 3| 2|             
                                           | 2| 1| 8| 8| 8| 1| 1| 0| 0| 8| 1| 0| 8| 8| 8| 1| 9| 8| 8| 5| 0| 0| 0| 0| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +        +                             A        +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +        +                             A        +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +        +                                      +     +               |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +        +                                      +     +               |             
      Diverticulum                         |                                                                          |             
      Mucosa, Inflammation, Suppurative    |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +        +  +  +  +  +     +  +        +  +  +  +  +  +  +  +  +  +  +|             
      Anisokaryosis                        |             2                                                            |             
      Autolysis                            |                                                                          |             
      Basophilic Focus                     |                                                                      X   |             
      Clear Cell Focus                     |                                                                          |             
      Cyst                                 |                                                                   4      |             
      Eosinophilic Focus                   |             X                 X                                          |             
      Focal Cellular Change                |                                                 X                        |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                         1                                                |             
      Inflammation, Chronic                |                                                                          |             
      Necrosis                             |                                                                          |             
      Syncytial Alteration                 |             2                                                            |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                       +                  |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +        +                             A        +  +  +               |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +        +                             +        +     +               |             
      Inflammation, Chronic                |    1                                                     2               |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +        +                             A        +  +  +               |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +        +                                      +  +  +               |             
                                            __________________________________________________________________________|             
   Tooth                                   |    +                                                                     |             
      Pulp, Necrosis                       |    3                                                                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +        +                             +        +  +  +               |             
      Inflammation, Acute                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +        +  +  +  +  +     +  +        +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +        +  +  +  +  +     +  +        +  +  +  +  +  +  +  +  +  +   |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  54                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 4| 4| 2| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 0| 5| 5| 6| 3| 3| 3| 3| 5| 3| 3| 5| 5| 1| 3| 2| 8| 4| 6| 3| 3| 3| 3| 2|             
                                           | 2| 1| 8| 8| 8| 1| 1| 0| 0| 8| 1| 0| 8| 8| 8| 1| 9| 8| 8| 5| 0| 0| 0| 0| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Degeneration, Focal                  |                                                             3            |             
      Hyperplasia, Focal                   |                                                                          |             
      Spindle Cell, Subcapsular,           |                                                                          |             
          Proliferation                    |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +        +  +  +  +  +     +  +        +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                              3                          3|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +        +                             A        +  +  +               |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +        +                             +        +  M  +               |             
      Pars Distalis, Hyperplasia, Focal    |    3                                                                     |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +        +  +  +  +  +     +  +        +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                   2                                                      |             
      Inflammation, Suppurative            |                                                                          |             
      Follicular Cell, Hyperplasia         |                2                             2  2           1     1     1|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +                                                                    +|             
      Inflammation, Chronic                |    3                                                                     |             
      Inflammation, Suppurative            |                                                                         4|             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +        +                             +        +  +  +               |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +        +                             +        +  +  +              +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +        +                 +  +        +        +  +  +  +           +|             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid, Plasma Cell   | 4                                                                        |             
      Hyperplasia, Plasma Cell             |                                                                          |             
      Iliac, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                                                                          |             
      Iliac, Hyperplasia                   |                                                                          |             
      Iliac, Hyperplasia, Plasma Cell      |                                                             4            |             
      Inguinal, Hyperplasia, Lymphoid      |                                                    3                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +        M                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | M  +        +                 +  +        M        +  +  +  +           +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  55                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 4| 4| 2| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 0| 5| 5| 6| 3| 3| 3| 3| 5| 3| 3| 5| 5| 1| 3| 2| 8| 4| 6| 3| 3| 3| 3| 2|             
                                           | 2| 1| 8| 8| 8| 1| 1| 0| 0| 8| 1| 0| 8| 8| 8| 1| 9| 8| 8| 5| 0| 0| 0| 0| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Congestion                           |                                  4                          4           3|             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +        +  +  +  +  +     +  +        A  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |    4                          3                 3           4     4     3|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  M        +                             +        +     +               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M                                         M        M  M  M               |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +        +           +                 +        +  +  +  +     +      |             
      Acanthosis                           | 3                                                  3                     |             
      Atrophy                              |                                                    3                     |             
      Inflammation, Chronic                |                                                                          |             
      Ulcer                                |                         4                                   4            |             
      Dermis, Inflammation, Chronic        | 3                                                                        |             
      Prepuce, Inflammation, Suppurative   |             3                                                            |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                         4                                                |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +        +        +        +           +     +  +  +  +              +|             
      Hyperostosis                         |                                                                          |             
      Joint, Tarsal, Hyperostosis          |                      X        X                 X                       X|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +        +                             +        +  +  +               |             
      Cyst Epithelial Inclusion            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +        +                 +           +        +  +  +  +  +     +   |             
      Congestion                           |             4                 3                                      3   |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Atypical                        |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                       2                  |             
      Alveolus, Hyperplasia, Macrophage    |                                                                          |             
      Vein, Leukocytosis                   |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +        +                             +        +  +  +               |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +        +                             A        +  +  +               |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                              +                           |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  56                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 4| 3| 7| 7| 7| 7| 4| 7| 7| 4| 4| 2| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 0| 5| 5| 6| 3| 3| 3| 3| 5| 3| 3| 5| 5| 1| 3| 2| 8| 4| 6| 3| 3| 3| 3| 2|             
                                           | 2| 1| 8| 8| 8| 1| 1| 0| 0| 8| 1| 0| 8| 8| 8| 1| 9| 8| 8| 5| 0| 0| 0| 0| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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|             
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +        +                             +        +  +  +               |             
      Cytoplasmic Alteration               |                                                                          |             
      Inflammation, Chronic                | 1  1        1                                      1     2               |             
      Inflammation, Suppurative            |                                                                          |             
      Nephropathy                          |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +        +                             A        +  +  +               |             
      Submucosa, Inflammation, Chronic     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  57                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 7| 7| 6| 4| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 5| 0| 4|             
                             DAY ON TEST   | 3| 2| 2| 9| 5| 2| 2| 8| 5| 7| 2| 2| 2| 2| 5| 3| 3| 3| 3| 2| 3| 5| 4| 1| 5|             
                                           | 1| 9| 9| 1| 6| 9| 9| 4| 8| 9| 9| 9| 9| 9| 4| 1| 1| 1| 0| 9| 0| 2| 7| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    50 MG/KG                               | 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Gallbladder                             |          M  A  +     +     A              +                    M  A      |             
                                            __________________________________________________________________________|             
   Intestine Large                         |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  |          +  +        +     A              +                    +  A      |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  |          +  +        +     +              +                    +  A      |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small                         |          +  A        +     +              +        +  +        +  A      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               |          +                 +              +                    +  A      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  |          +                 A              +        +           +  A      |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                |          +           +     A              +           +        +  A      |             
      Diverticulum                         |                                                                          |             
      Mucosa, Inflammation, Suppurative    |                      4                                                   |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
      Anisokaryosis                        |                   1                                                      |             
      Autolysis                            |                                                                   4      |             
      Basophilic Focus                     |                                              X  X     X                  |             
      Clear Cell Focus                     |                                                                          |             
      Cyst                                 |                                                                          |             
      Eosinophilic Focus                   |                                  X                                       |             
      Focal Cellular Change                |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Chronic                |                               2                                          |             
      Necrosis                             |                                                                          |             
      Syncytial Alteration                 |                1                             1                           |             
                                            __________________________________________________________________________|             
   Mesentery                               |          +                                                        +      |             
      Inflammation, Chronic                |          3                                                               |             
      Inflammation, Suppurative            |                                                                   4      |             
                                            __________________________________________________________________________|             
   Pancreas                                |          +  +        +     +              +                    +  M      |             
                                            __________________________________________________________________________|             
   Salivary Glands                         |          +  +        +     +              +                    +  +      |             
      Inflammation, Chronic                |          2  2        1                    1                    2         |             
                                            __________________________________________________________________________|             
   Stomach                                 |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                                          |             
      Pulp, Necrosis                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   |          +  +        +     +              +                    +  +      |             
      Inflammation, Acute                  |                                                                   1      |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +  M  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  58                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 7| 7| 6| 4| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 5| 0| 4|             
                             DAY ON TEST   | 3| 2| 2| 9| 5| 2| 2| 8| 5| 7| 2| 2| 2| 2| 5| 3| 3| 3| 3| 2| 3| 5| 4| 1| 5|             
                                           | 1| 9| 9| 1| 6| 9| 9| 4| 8| 9| 9| 9| 9| 9| 4| 1| 1| 1| 0| 9| 0| 2| 7| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    50 MG/KG                               | 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Degeneration, Focal                  |                                                                          |             
      Hyperplasia, Focal                   |                                              1                           |             
      Spindle Cell, Subcapsular,           |                                                                          |             
          Proliferation                    |                   4                                                      |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | M  +  +  +     +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
      Hyperplasia, Focal                   |                      1                                                   |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      |          +  +        +     +              +                    +  M      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       |          +  +        +     +              M                    +  M      |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         |          +  +        +     +              M                    +  +      |             
      Pars Distalis, Hyperplasia, Focal    |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Suppurative            |    2                                                                     |             
      Follicular Cell, Hyperplasia         |    1           1     1              1     1  2        1  2               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |             +                                                            |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |    +  +     +                                            +               |             
      Inflammation, Chronic                |       4                                                                  |             
      Inflammation, Suppurative            |    4        4                                            4               |             
      Duct, Ectasia                        |       4                                                                  |             
                                            __________________________________________________________________________|             
   Prostate                                |          +  +        +     +              +                    +  +      |             
      Inflammation, Chronic                |          4                                                               |             
      Inflammation, Suppurative            |                                                                   4      |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Testes                                  |          +  +        +     +              +                    +  +      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Lymph Node                              |          +  +        +     +     +        +        +  +  +     +  +      |             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |             
      Hyperplasia, Plasma Cell             |                                                          3               |             
      Iliac, Hematopoietic Cell            |                                                                          |             
          Proliferation                    |                                                                          |             
      Iliac, Hyperplasia                   |                                                                   3      |             
      Iliac, Hyperplasia, Plasma Cell      |                                                                          |             
      Inguinal, Hyperplasia, Lymphoid      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  |          +  +        +     +     +        +                    +  +      |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  |          +  +        +     +     +        +        +           +  A      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  59                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 7| 7| 6| 4| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 5| 0| 4|             
                             DAY ON TEST   | 3| 2| 2| 9| 5| 2| 2| 8| 5| 7| 2| 2| 2| 2| 5| 3| 3| 3| 3| 2| 3| 5| 4| 1| 5|             
                                           | 1| 9| 9| 1| 6| 9| 9| 4| 8| 9| 9| 9| 9| 9| 4| 1| 1| 1| 0| 9| 0| 2| 7| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    50 MG/KG                               | 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Congestion                           |                                                                4         |             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  A      |             
      Hematopoietic Cell Proliferation     |                4              3     4     4              4  4            |             
                                            __________________________________________________________________________|             
   Thymus                                  |          M  +        M     M     +        M                    M  M      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           |          M  M        M     M              M                    M  M      |             
                                            __________________________________________________________________________|             
   Skin                                    |       +  +  +  +  +  +     +  +     +     +  +  +     +  +  +  +  +      |             
      Acanthosis                           |                                              4                           |             
      Atrophy                              |                                           3                    3         |             
      Inflammation, Chronic                |                                                                          |             
      Ulcer                                |                                              4  4        4               |             
      Dermis, Inflammation, Chronic        |                                                                          |             
      Prepuce, Inflammation, Suppurative   |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Suppurative                     |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    |       +  +  +  +  +  +     +  +  +  +  +  +        +  +        +  +      |             
      Hyperostosis                         |       X           X           X     X                                    |             
      Joint, Tarsal, Hyperostosis          |                X                 X     X           X  X                  |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   |          +  +        +     +              +                    +  +      |             
      Cyst Epithelial Inclusion            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    |       +  +  +     +  +     +        +  +  +  +     +           +  +      |             
      Congestion                           |                                                                          |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Atypical                        |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolus, Hyperplasia, Macrophage    |                   4                                                      |             
      Vein, Leukocytosis                   |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    |          +  +        +     +              +                    +  +      |             
                                            __________________________________________________________________________|             
   Trachea                                 |          +  +        +     +              +                    +  +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         | +                                                                        |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  60                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 7| 7| 6| 4| 4| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 5| 0| 4|             
                             DAY ON TEST   | 3| 2| 2| 9| 5| 2| 2| 8| 5| 7| 2| 2| 2| 2| 5| 3| 3| 3| 3| 2| 3| 5| 4| 1| 5|             
                                           | 1| 9| 9| 1| 6| 9| 9| 4| 8| 9| 9| 9| 9| 9| 4| 1| 1| 1| 0| 9| 0| 2| 7| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    50 MG/KG                               | 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  |          +  +        +     +              +                    +  +      |             
      Cytoplasmic Alteration               |                                                                          |             
      Inflammation, Chronic                |          3  1        1                    1                              |             
      Inflammation, Suppurative            |                                                                   4      |             
      Nephropathy                          |                                                                2         |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         |          +           +     +              +                    +  +      |             
      Submucosa, Inflammation, Chronic     |          4                                                               |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  61                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 7| 7| 4| 7| 7| 4| 7| 5|                             |            |
                             DAY ON TEST   | 3| 2| 5| 5| 5| 3| 3| 3| 2| 5| 3| 3| 4| 3| 9|                             |            |
                                           | 0| 9| 4| 8| 8| 1| 0| 0| 9| 8| 1| 0| 1| 0| 6|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             |                                     +     A                              |  11        |
                                            __________________________________________________________________________|____________|
   Intestine Large                         |       +                             A     +                              |  15        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  |       +                                   +                              |  13        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  |       +                                   +                              |  14        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 |       +                                   +                              |  15        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         |       +           +                 A     +                              |  16        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               |                                           +                              |  10        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  |                                           M                              |  10        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                |       +           +                       +                              |  13        |
      Diverticulum                         |                   3                                                      |      1  3.0|
      Mucosa, Inflammation, Suppurative    |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +        +  +  +  +     +  +  +  +  +                              |  54        |
      Anisokaryosis                        |                                                                          |      2  1.5|
      Autolysis                            |                                                                          |      1  4.0|
      Basophilic Focus                     |                                        X                                 |      5     |
      Clear Cell Focus                     |                                  X     X                                 |      2     |
      Cyst                                 |                                                                          |      1  4.0|
      Eosinophilic Focus                   |                                                                          |      3     |
      Focal Cellular Change                |                                                                          |      1     |
      Hematopoietic Cell Proliferation     |       3                                                                  |      1  3.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  1.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Necrosis                             |       3                             3                                    |      2  3.0|
      Syncytial Alteration                 |                                                                          |      3  1.3|
                                            __________________________________________________________________________|____________|
   Mesentery                               |       +                                                                  |   4        |
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                |       +                             +     +                              |  15        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         |       +                             +     +                              |  16        |
      Inflammation, Chronic                |                                     2                                    |      8  1.6|
                                            __________________________________________________________________________|____________|
   Stomach                                 |       +                             A     +                              |  15        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    |       +                                   +                              |  15        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      |       +                                   +                              |  15        |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   1        |
      Pulp, Necrosis                       |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   |       +                             +     +                              |  17        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  62                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 7| 7| 4| 7| 7| 4| 7| 5|                             |            |
                             DAY ON TEST   | 3| 2| 5| 5| 5| 3| 3| 3| 2| 5| 3| 3| 4| 3| 9|                             |            |
                                           | 0| 9| 4| 8| 8| 1| 0| 0| 9| 8| 1| 0| 1| 0| 6|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
      Inflammation, Acute                  |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           | +  +  +        +  +  +  +     +  +  +  +  +                              |  53        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   | +  +  +        +  +  +  +     +  +  +  +  +                              |  52        |
      Degeneration, Focal                  |                                                                          |      1  3.0|
      Hyperplasia, Focal                   |                      3                                                   |      2  2.0|
      Spindle Cell, Subcapsular,           |                                                                          |            |
          Proliferation                    |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  | +  +  +        +  +  +  +     +  +  +  +  +                              |  52        |
      Hyperplasia, Focal                   |                                                                          |      3  2.3|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      |       +                             +     +                              |  15        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       |       +                             +     +                              |  15        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         |       M                             +     +                              |  14        |
      Pars Distalis, Hyperplasia, Focal    |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +        +  +  +  +     +  +  +     +                              |  53        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Inflammation, Suppurative            |                                                                          |      1  2.0|
      Follicular Cell, Hyperplasia         |                      1                                                   |     15  1.3|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Coagulating Gland                       |                                     +                                    |   1        |
                                            __________________________________________________________________________|____________|
   Epididymis                              |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         |                                     +  +  +                              |   9        |
      Inflammation, Chronic                |                                           3                              |      3  3.3|
      Inflammation, Suppurative            |                                     4  4                                 |      6  4.0|
      Duct, Ectasia                        |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Prostate                                |       +                             +     +                              |  17        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Testes                                  |       +                             +     +                              |  18        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +     +           +  +  +           +     +                              |  29        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  63                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 7| 7| 4| 7| 7| 4| 7| 5|                             |            |
                             DAY ON TEST   | 3| 2| 5| 5| 5| 3| 3| 3| 2| 5| 3| 3| 4| 3| 9|                             |            |
                                           | 0| 9| 4| 8| 8| 1| 0| 0| 9| 8| 1| 0| 1| 0| 6|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Congestion                           |                   4                                                      |      1  4.0|
      Hyperplasia, Lymphoid, Plasma Cell   |                                                                          |      1  4.0|
      Hyperplasia, Plasma Cell             |                                                                          |      1  3.0|
      Iliac, Hematopoietic Cell            |                                                                          |            |
          Proliferation                    |       4                                                                  |      1  4.0|
      Iliac, Hyperplasia                   |                                                                          |      1  3.0|
      Iliac, Hyperplasia, Plasma Cell      |                                                                          |      1  4.0|
      Inguinal, Hyperplasia, Lymphoid      |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +     +              +  +           +     +                              |  23        |
      Congestion                           |                      3  4                                                |      6  3.7|
      Hematopoietic Cell Proliferation     |       4                                                                  |      1  4.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +        +  +  +  +     +  +  +  +  +                              |  52        |
      Hematopoietic Cell Proliferation     |       4                                   4                              |     14  3.7|
                                            __________________________________________________________________________|____________|
   Thymus                                  |       +                             +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           |       M                             M     M                              |            |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +              +              +     +                              |  33        |
      Acanthosis                           |                                                                          |      3  3.3|
      Atrophy                              |                                                                          |      3  3.0|
      Inflammation, Chronic                |                      3                                                   |      1  3.0|
      Ulcer                                |    4                                                                     |      6  4.0|
      Dermis, Inflammation, Chronic        |                                                                          |      1  3.0|
      Prepuce, Inflammation, Suppurative   |                                                                          |      1  3.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Suppurative                     |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    |    +  +                          +  +     +                              |  32        |
      Hyperostosis                         |    X                                                                     |      5     |
      Joint, Tarsal, Hyperostosis          |                                  X                                       |     10     |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   |       +                             +     +                              |  17        |
      Cyst Epithelial Inclusion            |                                           X                              |      1     |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +     +        +        +     +     +     +                              |  31        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  64                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 4| 4| 7| 7| 7| 7| 4| 7| 7| 4| 7| 5|                             |            |
                             DAY ON TEST   | 3| 2| 5| 5| 5| 3| 3| 3| 2| 5| 3| 3| 4| 3| 9|                             |            |
                                           | 0| 9| 4| 8| 8| 1| 0| 0| 9| 8| 1| 0| 1| 0| 6|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    50 MG/KG                               | 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Congestion                           |                         3                                                |      4  3.3|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Atypical                        |                               2                                          |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      1  2.0|
      Alveolus, Hyperplasia, Macrophage    |                                                                          |      1  4.0|
      Vein, Leukocytosis                   |       X                                                                  |      1     |
                                            __________________________________________________________________________|____________|
   Nose                                    |       +                             +     +                              |  17        |
                                            __________________________________________________________________________|____________|
   Trachea                                 |       +                             +     +                              |  16        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                         +                                                |   2        |
                                            __________________________________________________________________________|____________|
   Lacrimal Gland                          |                               +                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  |       +                             +     +                              |  17        |
      Cytoplasmic Alteration               |       2                                                                  |      1  2.0|
      Inflammation, Chronic                |                                     2     1                              |     11  1.4|
      Inflammation, Suppurative            |                                                                          |      1  4.0|
      Nephropathy                          |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         |       +                             +     +                              |  15        |
      Submucosa, Inflammation, Chronic     |       1                                                                  |      2  2.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  65                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 7| 7| 7| 5| 7| 7| 7| 7| 7| 4| 6| 7| 6| 4| 3|             
                             DAY ON TEST   | 3| 3| 3| 6| 5| 3| 3| 2| 2| 5| 3| 3| 3| 2| 2| 3| 3| 2| 2| 5| 8| 3| 8| 5| 3|             
                                           | 0| 0| 4| 3| 8| 1| 0| 9| 5| 8| 1| 0| 0| 6| 9| 1| 0| 9| 9| 8| 1| 1| 0| 8| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  A     +|             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  A     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  A     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  A     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  A     +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  A     +|             
      Mucosa, Necrosis                     |                         4                                                |             
      Peyer's Patch, Hyperplasia, Lymphoid |                         4                                                |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A     +  +  +  +     +  +  +  A     +  +  +  +     +  +  A     +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Amyloid Deposition                   |                                                                          |             
      Anisokaryosis                        |                   1  1                             1                     |             
      Basophilic Focus                     |          X                       X           X  X                        |             
      Cyst                                 |                                                                          |             
      Cytomegaly                           |       1        2                          1                              |             
      Eosinophilic Focus                   | X              X                                                         |             
      Fatty Change                         |                      2                                                   |             
      Hyperplasia, Re Cell                 |                                                                          |             
      Infarct                              |                                                       4                  |             
      Inflammation, Chronic                |                               3                                          |             
      Mixed Cell Focus                     |                                                                X         |             
      Necrosis                             |                                                                          |             
      Syncytial Alteration                 |    1  2              2  3           1     2     1     1     1  1  1      |             
      Centrilobular, Degeneration,         |                                                                          |             
          Ballooning                       |                                              3                           |             
      Sinusoid, Dilatation, Focal          |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |       +                 +                          +                    +|             
      Inflammation, Acute                  |                         4                                                |             
      Inflammation, Chronic                |                                                                          |             
      Fat, Inflammation, Chronic           |                                                    3                     |             
      Fat, Necrosis, Focal                 |       4                                                                  |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
      Inflammation, Chronic                |                   1                                                      |             
      Acinus, Vacuolization Cytoplasmic    |                                                                          |             
      Serosa, Inflammation, Acute          |                         3                                                |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Concretion, Chronic                  |                                                    2                     |             
      Inflammation, Chronic                | 2              1     2        1           1  2        2     1  2  1     2|             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
 _____________________________________________________________________________________________________________________|             
                                                             Page  66                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 7| 7| 7| 5| 7| 7| 7| 7| 7| 4| 6| 7| 6| 4| 3|             
                             DAY ON TEST   | 3| 3| 3| 6| 5| 3| 3| 2| 2| 5| 3| 3| 3| 2| 2| 3| 3| 2| 2| 5| 8| 3| 8| 5| 3|             
                                           | 0| 0| 4| 3| 8| 1| 0| 9| 5| 8| 1| 0| 0| 6| 9| 1| 0| 9| 9| 8| 1| 1| 0| 8| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Acanthosis                           |                         4                                                |             
      Ulcer                                |                         4                                                |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Ulcer                                |                         3                                                |             
                                            __________________________________________________________________________|             
   Tooth                                   |                   +              +                                       |             
      Peridontal Tissue, Inflammation,     |                                                                          |             
           Suppurative                     |                   2                                                      |             
      Pulp, Abscess                        |                                  3                                       |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Cardiomyopathy                       |                                                                          |             
      Atrium Left, Thrombosis              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Hyperplasia, Focal                   |                                                    3                     |             
      Hypertrophy, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Hyperplasia, Focal                   |                                                             2            |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +     +  +  +  +     +  +  +  M  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M     +  +  +  M     +  M  +  +  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  M  +  +     +  +  M  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Pars Distalis, Hyperplasia, Focal    | 1              3                    2                                    |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Inflammation, Chronic                |                         2                                                |             
      Follicle, Inflammation, Acute        |                                                                2         |             
      Follicular Cell, Hyperplasia         | 1        2              2        3        1     1     2     2  2         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +     +  M  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Inflammation, Chronic                |                                                    3              3      |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |                                              +                           |             
      Inflammation, Chronic                |                                              4                           |             
      Inflammation, Suppurative            |                                                                          |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Inflammation, Acute                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  67                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 7| 7| 7| 5| 7| 7| 7| 7| 7| 4| 6| 7| 6| 4| 3|             
                             DAY ON TEST   | 3| 3| 3| 6| 5| 3| 3| 2| 2| 5| 3| 3| 3| 2| 2| 3| 3| 2| 2| 5| 8| 3| 8| 5| 3|             
                                           | 0| 0| 4| 3| 8| 1| 0| 9| 5| 8| 1| 0| 0| 6| 9| 1| 0| 9| 9| 8| 1| 1| 0| 8| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Inflammation, Chronic                |                                                    1                     |             
      Serosa, Inflammation, Acute          |                         2                                                |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Serosa, Inflammation, Acute          |                         2                                                |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Atrophy                              |    4                                                                     |             
      Germinal Epithelium, Degeneration    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Hyperplasia, Lymphoid                |       3                                                                  |             
      Inflammation, Acute                  |                         4                                                |             
      Axillary, Hyperplasia, Plasma Cell   |       4                                                                  |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +     +        +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Hyperplasia, Plasma Cell             |                                           4           4                  |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +     +  M  +        +  M  +  M  +  +  +  M  +     +  +  +     +|             
      Congestion                           |    3  4        4     4              3        4        4                  |             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +     +  +  +  +     +  +  +  A  +  +  +  +  +     +  +  +     +|             
      Amyloid Deposition                   |                                                                          |             
      Hematopoietic Cell Proliferation     |       4                       4                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +     +  +  +  +     +  +  +  M  +  +  +  +  +     +  +  M     M|             
      Amyloid Deposition                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 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|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Acanthosis                           |       3                                                                  |             
      Alopecia                             |       X                                                                  |             
      Atrophy                              |                               3                                          |             
      Inflammation, Chronic                |                                        4                                 |             
      Ulcer                                |       4                          4  2  4  4           4                  |             
      Dermis, Inflammation, Chronic        |                                     3                                    |             
      Dermis, Dorsal, Atrophy              |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Chronic                         |                                                                          |             
      Tail, Dermis, Inflammation           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Joint, Tarsal, Hyperostosis          |                               X                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  68                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 5| 4| 7| 7| 7| 6| 4| 7| 7| 7| 5| 7| 7| 7| 7| 7| 4| 6| 7| 6| 4| 3|             
                             DAY ON TEST   | 3| 3| 3| 6| 5| 3| 3| 2| 2| 5| 3| 3| 3| 2| 2| 3| 3| 2| 2| 5| 8| 3| 8| 5| 3|             
                                           | 0| 0| 4| 3| 8| 1| 0| 9| 5| 8| 1| 0| 0| 6| 9| 1| 0| 9| 9| 8| 1| 1| 0| 8| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Mineralization                       |          1              1                                                |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                     +                                   +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Hemorrhage                           |                               2                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolus, Hyperplasia, Macrophage    |                4                                                         |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Lumen, Turbinate, Inflammation,      |                                                                          |             
          Suppurative                      |                                                                          |             
      Mucosa, Inflammation, Chronic        |                                                                          |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         | +  +                 +                                                   |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                                                          |             
      Extraorbital, Inflammation, Chronic  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Amyloid Deposition                   |                                                                          |             
      Glomerulosclerosis                   |                                                    4                     |             
      Inflammation, Chronic                | 2  2  2        2  1  2        3     2     1  2  1  3  2        2         |             
      Nephropathy                          |                                                             4            |             
      Renal Tubule, Mineralization         |                                                                          |             
                                            __________________________________________________________________________|             
   Urethra                                 |                                                                          |             
      Distal, Concretion                   |                                                                          |             
      Distal, Inflammation, Suppurative    |                                                                          |             
      Proximal, Inflammation, Suppurative  |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +     +  +  +  +     +  +  +  +  +  +  +  +  +     +  +  +     +|             
      Muscularis, Hemorrhage               |                                                                          |             
      Submucosa, Inflammation, Chronic     |                   1  1                             3                     |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  69                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 6| 6| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 6| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 5| 4| 5| 5| 3| 3| 3| 9| 5| 3| 3| 2| 5| 3| 3| 2| 4| 5| 5|             
                                           | 1| 0| 9| 9| 3| 0| 7| 2| 8| 8| 1| 1| 0| 7| 8| 1| 0| 9| 5| 5| 0| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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   | 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|             
    100MG/KG                               | 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  A  +  M  +        +  +  +  +     +  +  +  M  M  +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large                         | +  +  +  +  +  +  +  A        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  A        +  +  +  +     +  +  +  A  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  A  A        +  +  +  +     +  +  +  A  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small                         | +  +  +  +  A  +  +  A        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  A        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  A        +  +  +  +     +  +  +  A  +  +  +  +      |             
      Mucosa, Necrosis                     |                                                                          |             
      Peyer's Patch, Hyperplasia, Lymphoid |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  A  +  +  A        +  +  +  +     +  +  +  A  +  +  +  +      |             
      Hyperplasia, Lymphoid                |                                                             3            |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Anisokaryosis                        |    1                                         1        1  1               |             
      Basophilic Focus                     |       X                       X  X  X                                    |             
      Cyst                                 |                                                                          |             
      Cytomegaly                           |                                                                          |             
      Eosinophilic Focus                   |                                     X                                    |             
      Fatty Change                         | 2                                                                        |             
      Hyperplasia, Re Cell                 |                                                                          |             
      Infarct                              |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |             4        4                                                   |             
      Syncytial Alteration                 | 1                 2  2        1              2     1     2  2            |             
      Centrilobular, Degeneration,         |                                                                          |             
          Ballooning                       |                                                                          |             
      Sinusoid, Dilatation, Focal          |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                +                                                         |             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic                |                2                                                         |             
      Fat, Inflammation, Chronic           |                                                                          |             
      Fat, Necrosis, Focal                 |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Inflammation, Chronic                |          1                                                               |             
      Acinus, Vacuolization Cytoplasmic    |                3                                                         |             
      Serosa, Inflammation, Acute          |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Concretion, Chronic                  |                                                                          |             
      Inflammation, Chronic                | 1  2     2     2     1           2  2        2  1  2  1     1            |             
                                            __________________________________________________________________________|             
   Stomach                                 | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  70                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 6| 6| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 6| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 5| 4| 5| 5| 3| 3| 3| 9| 5| 3| 3| 2| 5| 3| 3| 2| 4| 5| 5|             
                                           | 1| 0| 9| 9| 3| 0| 7| 2| 8| 8| 1| 1| 0| 7| 8| 1| 0| 9| 5| 5| 0| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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   | 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|             
    100MG/KG                               | 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  M  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Acanthosis                           |                                                                          |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                                          |             
      Peridontal Tissue, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                          |             
      Pulp, Abscess                        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Cardiomyopathy                       |                                                                          |             
      Atrium Left, Thrombosis              |                                                          X               |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Gland                           | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Hyperplasia, Focal                   | 1  2                                2           1                        |             
      Hypertrophy, Focal                   |                                                    1                     |             
                                            __________________________________________________________________________|             
   Adrenal Gland, Medulla                  | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Hyperplasia, Focal                   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  +  +  +  +        +  +  +  M     +  +  +  M  +  +  M  +      |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | M  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Pars Distalis, Hyperplasia, Focal    |                                              3                 3         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  M  +      |             
      Inflammation, Chronic                |                                                    1                     |             
      Follicle, Inflammation, Acute        |                                                                          |             
      Follicular Cell, Hyperplasia         |    2           1              1  3              2  1                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Coagulating Gland                       |                                                 +           +            |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         |       +                                +     +        +     +            |             
      Inflammation, Chronic                |                                                             1            |             
      Inflammation, Suppurative            |                                        4     4        4                  |             
      Duct, Ectasia                        |                                                             4            |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Inflammation, Acute                  |                   2                                                      |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  71                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 6| 6| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 6| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 5| 4| 5| 5| 3| 3| 3| 9| 5| 3| 3| 2| 5| 3| 3| 2| 4| 5| 5|             
                                           | 1| 0| 9| 9| 3| 0| 7| 2| 8| 8| 1| 1| 0| 7| 8| 1| 0| 9| 5| 5| 0| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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   | 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|             
    100MG/KG                               | 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Inflammation, Chronic                | 1        2                                            1     1            |             
      Serosa, Inflammation, Acute          |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Serosa, Inflammation, Acute          |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Atrophy                              |                                                                          |             
      Germinal Epithelium, Degeneration    | 3                                                                        |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  +  +  +        M  +  +  +     +  +  +  +  +  +  +  +      |             
      Hyperplasia, Plasma Cell             |                                                 4                 4      |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Congestion                           |                      4                                                   |             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hyperplasia, Lymphoid                |                3                                   3                     |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  M  +  M  M        +  +  +  M     +  +  +  +  +  +  M  +      |             
      Amyloid Deposition                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M        M  +  M  M     M  M  M  M  M  M  M  M      |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Acanthosis                           |                                                                          |             
      Alopecia                             |                                                                          |             
      Atrophy                              |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Ulcer                                |                      4                          3                 3      |             
      Dermis, Inflammation, Chronic        |                      2                                                   |             
      Dermis, Dorsal, Atrophy              |                      3                                                   |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Chronic                         |                                                                          |             
      Tail, Dermis, Inflammation           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Joint, Tarsal, Hyperostosis          |       X                       X              X     X                     |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  72                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 6| 6| 4| 4| 7| 7| 7| 6| 4| 7| 7| 7| 6| 6| 7| 7| 6| 4| 4|             
                             DAY ON TEST   | 3| 3| 2| 2| 6| 3| 5| 4| 5| 5| 3| 3| 3| 9| 5| 3| 3| 2| 5| 3| 3| 2| 4| 5| 5|             
                                           | 1| 0| 9| 9| 3| 0| 7| 2| 8| 8| 1| 1| 0| 7| 8| 1| 0| 9| 5| 5| 0| 9| 9| 8| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 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   | 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|             
    100MG/KG                               | 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Mineralization                       |                                                          1               |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                        +                 +               |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Hemorrhage                           |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolus, Hyperplasia, Macrophage    |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Lumen, Turbinate, Inflammation,      |                                                                          |             
          Suppurative                      |                                                             3            |             
      Mucosa, Inflammation, Chronic        |                                                                          |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic                         |    2                                                                     |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                 +                 +      |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                 +                 +      |             
                                            __________________________________________________________________________|             
   Lacrimal Gland                          |                                  +                                       |             
      Extraorbital, Inflammation, Chronic  |                                  3                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Amyloid Deposition                   |                                                                          |             
      Glomerulosclerosis                   |                                                                          |             
      Inflammation, Chronic                | 2  2  1  2  2  3  2           1  2  2  1     2  2  3  1  2  2  1  2      |             
      Nephropathy                          |                                                                          |             
      Renal Tubule, Mineralization         |                      2                                                   |             
                                            __________________________________________________________________________|             
   Urethra                                 |                   +  +                                                   |             
      Distal, Concretion                   |                   4                                                      |             
      Distal, Inflammation, Suppurative    |                   2                                                      |             
      Proximal, Inflammation, Suppurative  |                      4                                                   |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +        +  +  +  +     +  +  +  +  +  +  +  +      |             
      Muscularis, Hemorrhage               |                                                                          |             
      Submucosa, Inflammation, Chronic     |                2                 1                 2           1         |             
 _____________________________________________________________________________________________________________________|             
                                                             Page  73                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 6| 5| 7| 7| 7| 4| 7| 7| 7| 7| 4|                             |            |
                             DAY ON TEST   | 3| 2| 9| 8| 6| 7| 3| 3| 3| 5| 3| 3| 3| 3| 8|                             |            |
                                           | 1| 9| 0| 2| 1| 5| 1| 1| 0| 8| 1| 1| 1| 2| 1|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                             |      A     |
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  M     +  +  +  M  +                              |  48        |
      Inflammation, Chronic                |                               1                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Intestine Large                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  53        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  48        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  52        |
                                            __________________________________________________________________________|____________|
   Intestine Small                         | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  51        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  51        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +     +  +  +  +  M                              |  47        |
      Mucosa, Necrosis                     |                                                                          |      1  4.0|
      Peyer's Patch, Hyperplasia, Lymphoid |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  M  +     +  +  +  +  A                              |  45        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Amyloid Deposition                   |             4                                                            |      1  4.0|
      Anisokaryosis                        | 1     1  2           2  1                                                |     12  1.2|
      Basophilic Focus                     | X  X                    X                                                |     11     |
      Cyst                                 |       X                                                                  |      1     |
      Cytomegaly                           |                                                                          |      3  1.3|
      Eosinophilic Focus                   |          X                                                               |      4     |
      Fatty Change                         |                                           1                              |      3  1.7|
      Hyperplasia, Re Cell                 |                   2                                                      |      1  2.0|
      Infarct                              |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                                          |      2  4.0|
      Syncytial Alteration                 | 1     1  3              1        2  1                                    |     25  1.5|
      Centrilobular, Degeneration,         |                                                                          |            |
          Ballooning                       |                                                                          |      1  3.0|
      Sinusoid, Dilatation, Focal          |                   2                                                      |      1  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   5        |
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Fat, Inflammation, Chronic           |                                                                          |      1  3.0|
      Fat, Necrosis, Focal                 |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  53        |
      Inflammation, Chronic                |                                                                          |      2  1.0|
      Acinus, Vacuolization Cytoplasmic    |                                                                          |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  74                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 6| 5| 7| 7| 7| 4| 7| 7| 7| 7| 4|                             |            |
                             DAY ON TEST   | 3| 2| 9| 8| 6| 7| 3| 3| 3| 5| 3| 3| 3| 3| 8|                             |            |
                                           | 1| 9| 0| 2| 1| 5| 1| 1| 0| 8| 1| 1| 1| 2| 1|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                             |      A     |
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Serosa, Inflammation, Acute          |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Concretion, Chronic                  |                                                                          |      1  2.0|
      Inflammation, Chronic                | 1     2     1     2  2  2        2     2                                 |     31  1.6|
                                            __________________________________________________________________________|____________|
   Stomach                                 | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +     M  +  +  +  +                              |  53        |
      Acanthosis                           |                                                                          |      1  4.0|
      Ulcer                                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Ulcer                                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   2        |
      Peridontal Tissue, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      1  2.0|
      Pulp, Abscess                        |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Cardiomyopathy                       |             2                                                            |      1  2.0|
      Atrium Left, Thrombosis              |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Gland                           | +  +  +  +  +  +  +  +  +     M  +  +  +  +                              |  54        |
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Cortex                   | +  +  +  +  +  +  +  +  +        +  +  +  +                              |  54        |
      Hyperplasia, Focal                   |                         2                                                |      6  1.8|
      Hypertrophy, Focal                   |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Adrenal Gland, Medulla                  | +  +  +  +  +  +  +  +  +        +  +  +  +                              |  54        |
      Hyperplasia, Focal                   |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  A  +  +  +     +  +  +  +  +                              |  53        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  M  +  +  +  +  +  +     M  +  +  M  +                              |  44        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  M  +  +     M  +  +  +  +                              |  50        |
      Pars Distalis, Hyperplasia, Focal    |                                                                          |      5  2.4|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  54        |
      Inflammation, Chronic                |                                                                          |      2  1.5|
      Follicle, Inflammation, Acute        |                                                                          |      1  2.0|
      Follicular Cell, Hyperplasia         | 1                 1                 3  2                                 |     19  1.7|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Tissue NOS                              |    +                                                                     |   1        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  75                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 6| 5| 7| 7| 7| 4| 7| 7| 7| 7| 4|                             |            |
                             DAY ON TEST   | 3| 2| 9| 8| 6| 7| 3| 3| 3| 5| 3| 3| 3| 3| 8|                             |            |
                                           | 1| 9| 0| 2| 1| 5| 1| 1| 0| 8| 1| 1| 1| 2| 1|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                             |      A     |
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Coagulating Gland                       |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  54        |
      Inflammation, Chronic                |             2                                                            |      3  2.7|
                                            __________________________________________________________________________|____________|
   Preputial Gland                         |       +                                                                  |   7        |
      Inflammation, Chronic                |                                                                          |      2  2.5|
      Inflammation, Suppurative            |       4                                                                  |      4  4.0|
      Duct, Ectasia                        |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Inflammation, Acute                  |                                                                          |      1  2.0|
      Inflammation, Chronic                | 2           2           1        1                                       |      9  1.3|
      Serosa, Inflammation, Acute          |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Serosa, Inflammation, Acute          |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Atrophy                              |                                                                          |      1  4.0|
      Germinal Epithelium, Degeneration    |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Axillary, Hyperplasia, Plasma Cell   |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  51        |
      Hyperplasia, Plasma Cell             |                                     4                                    |      5  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  50        |
      Congestion                           | 3     4                                                                  |     10  3.7|
      Hematopoietic Cell Proliferation     |                                  3                                       |      1  3.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  54        |
      Amyloid Deposition                   |             4                                                            |      1  4.0|
      Hematopoietic Cell Proliferation     |                4              3  4  4                                    |      6  3.8|
      Hyperplasia, Lymphoid                |                                                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  M  M  +  +     +  +  M  M  M                              |  42        |
      Amyloid Deposition                   |             3                                                            |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M     M  M  M  M  M                              |   1        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  76                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 6| 5| 7| 7| 7| 4| 7| 7| 7| 7| 4|                             |            |
                             DAY ON TEST   | 3| 2| 9| 8| 6| 7| 3| 3| 3| 5| 3| 3| 3| 3| 8|                             |            |
                                           | 1| 9| 0| 2| 1| 5| 1| 1| 0| 8| 1| 1| 1| 2| 1|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                             |      A     |
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Acanthosis                           |          3                                                               |      2  3.0|
      Alopecia                             |                                                                          |      1     |
      Atrophy                              |                                                                          |      1  3.0|
      Inflammation, Chronic                |          3                                                               |      2  3.5|
      Ulcer                                |          4  4                 4  4  4                                    |     15  3.7|
      Dermis, Inflammation, Chronic        |                                                                          |      2  2.5|
      Dermis, Dorsal, Atrophy              |                                                                          |      1  3.0|
      Subcutaneous Tissue, Inflammation,   |                                                                          |            |
           Chronic                         |                      4                                                   |      1  4.0|
      Tail, Dermis, Inflammation           | 2                                                                        |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Joint, Tarsal, Hyperostosis          |    X                 X                                                   |      7     |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Mineralization                       |                                                                          |      3  1.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |          +           +                                                   |   6        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Hemorrhage                           |                                                                          |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |                      1                                                   |      1  1.0|
      Alveolus, Hyperplasia, Macrophage    |                                        3                                 |      2  3.5|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Lumen, Turbinate, Inflammation,      |                                                                          |            |
          Suppurative                      |                                                                          |      1  3.0|
      Mucosa, Inflammation, Chronic        |                                  2                                       |      1  2.0|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic                         |       2  2                                                               |      3  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     | +                                                                        |   3        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         | +                             +                                          |   7        |
                                            __________________________________________________________________________|____________|
   Lacrimal Gland                          |                                                                          |   1        |
      Extraorbital, Inflammation, Chronic  |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                             Page  77                                                               
NTP Experiment-Test: 05040-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 05/01/97  
Route: GAVAGE                                                                                                     Time: 10:16:48  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 6| 6| 5| 7| 7| 7| 4| 7| 7| 7| 7| 4|                             |            |
                             DAY ON TEST   | 3| 2| 9| 8| 6| 7| 3| 3| 3| 5| 3| 3| 3| 3| 8|                             |            |
                                           | 1| 9| 0| 2| 1| 5| 1| 1| 0| 8| 1| 1| 1| 2| 1|                             |      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 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|                             |      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|                             |      A     |
    100MG/KG                               | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9|                             |      L     |
                                           | 1| 2| 3| 4| 5| 1| 2| 3| 4| 5| 1| 2| 3| 4| 5|                             |            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Amyloid Deposition                   |             3                                                            |      1  3.0|
      Glomerulosclerosis                   |                                                                          |      1  4.0|
      Inflammation, Chronic                | 2  1  2  2  2     2  2  2        1  3  2                                 |     44  1.9|
      Nephropathy                          |                                                                          |      1  4.0|
      Renal Tubule, Mineralization         |                                           3                              |      2  2.5|
                                            __________________________________________________________________________|____________|
   Urethra                                 |                                                                          |   2        |
      Distal, Concretion                   |                                                                          |      1  4.0|
      Distal, Inflammation, Suppurative    |                                                                          |      1  2.0|
      Proximal, Inflammation, Suppurative  |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +     +  +  +  +  +                              |  55        |
      Muscularis, Hemorrhage               |                                           3                              |      1  3.0|
      Submucosa, Inflammation, Chronic     |       1  1  2        1           2  2                                    |     13  1.5|
 __________________________________________________________________________________________________________________________________ 
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.