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TDMS Study 55301-05 Pathology Tables

 
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97
Route: DOSED WATER                                                                                                Time: 10:52:14




       Facility:  TSI Mason Research

       Chemical CAS #:  110-86-1

       Lock Date:  12/15/94

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All






































                                                              Page   1


NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |                                                    X                     |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectopic Pancreas                     |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     | X  X        X  X  X     X     X  X  X     X     X  X  X  X  X  X  X     X|             
      Clear Cell Focus                     |                                                                X  X      |             
      Congestion                           |       2                                1                                2|             
      Developmental Malformation           |                                                                          |             
      Eosinophilic Focus                   | X           X  X                       X  X           X     X     X      |             
      Fibrosis                             |                                                                         1|             
      Hepatodiaphragmatic Nodule           |                   X  X                                   X  X           X|             
      Inflammation, Chronic Active         |    1        1  2     1  1                    3                           |             
      Mitotic Alteration                   |                                     1                                    |             
      Mixed Cell Focus                     |                                           X                              |             
      Necrosis                             |       2        1     1              1                                    |             
      Pigmentation                         |          2                             1     3                           |             
      Tension Lipidosis                    |             X        X                                                  X|             
      Vacuolization Cytoplasmic            |          4              2           2                       1  1         |             
      Bile Duct, Hyperplasia               |             1  1  1     1  1     1  1           1                 1  1  1|             
      Centrilobular, Degeneration          |                                                                          |             
      Centrilobular, Necrosis              |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +              +        +                          +                  |             
      Fat, Necrosis                        |    2              2        2                                             |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |    +                 +                                                   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Atrophy                              | 2  1           2     1  2  1  1  1     1        1        1        1     1|             
      Cytoplasmic Alteration               |                         1                                                |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis                       |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic Active         |          4                                                               |             
      Ulcer                                |          3                                                               |             
      Epithelium, Hyperplasia, Squamous    |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page   2                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Erosion                              |          4                                                           2   |             
      Inflammation, Chronic Active         |                                                                          |             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +|             
      Cardiomyopathy                       | 2  1  2  1     1  1        1     1  1  1  1  1  1  1  1  1     2  1     1|             
      Inflammation, Chronic Active         |             1                                                            |             
      Mineralization                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Adrenal Cortical Nodule    |                            2                                             |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hemorrhage                           |                                                                          |             
      Hyperplasia                          |                   1              1           1                    1      |             
      Vacuolization Cytoplasmic            |          1                 2        1     4                              |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                               3           1                              |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           | 3  2        2     2                             3              3        4|             
      Pars Distalis, Cyst                  |          2        2                          2     1  2  1  4     3      |             
      Pars Distalis, Hemorrhage            |                                                                          |             
      Pars Distalis, Hyperplasia           | 3  1     4        1  1                       2  4  1  2  2     4  1      |             
      Pars Intermedia, Hyperplasia         |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  | 1           2           1        1  1        1  1     1  1  2     1      |             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                          1               |             
      Inflammation, Acute                  |                                                          2               |             
      Inflammation, Chronic                |                   1                                                      |             
      Inflammation, Chronic Active         |                                                                3         |             
      Duct, Ectasia                        | 1                                                                       1|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                    2                     |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   3                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Cyst                                 |                                                             2            |             
      Inflammation, Chronic                |                                                    2                     |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Cystic                  |                                                                   1     1|             
      Necrosis                             |                                                    3                     |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                          |             
      Fibrosis                             |          1                                                               |             
      Hyperplasia                          |                            2                                             |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                            +                       +  +              +   |             
      Iliac, Congestion                    |                                                    2                     |             
      Mediastinal, Congestion              |                                                    2                     |             
      Mediastinal, Pigmentation            |                                                                          |             
      Renal, Congestion                    |                                                    1                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                   1                                                      |             
      Ectasia                              |    1                                                              2      |             
      Hyperplasia, Lymphoid                | 3                                                                        |             
      Hyperplasia, Plasma Cell             |          3                                                               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |             2                                                           2|             
      Hemorrhage                           |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                     3                                    |             
      Fibrosis                             |                                     2                                    |             
      Hematopoietic Cell Proliferation     |                                                    2                     |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectopic Parathyroid Gland            |                                                                          |             
      Inflammation, Acute                  |                                                                3         |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                                          3               |             
      Hyperplasia                          |                                              2        3  3               |             
      Duct, Dilatation                     | 1  1        3  1                 3           1                          3|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                          |             
      Inflammation, Acute                  |                      2                                                   |             
      Inflammation, Chronic                |                                              3                           |             
      Inflammation, Chronic Active         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   4                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Osteopetrosis                        |                         3     3           3        4                 2   |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                       +           +      |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                         3|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                2                                                         |             
      Infiltration Cellular, Histiocyte    |    1     1        1  1                 1        1     1           1      |             
      Inflammation, Chronic                |                         1  2     1           1           1               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                         2|             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Chronic Active         |             3           2                 1  1  1        1               |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic Active                  | 2                                                                        |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                             +            |             
      Inflammation, Chronic                |                                                             1            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                        2                                2|             
      Mineralization                       |                            1                       2                     |             
      Nephropathy                          | 2     2     1  1  2  1  1     2  2  2     1  1  1  1     1  1  1  2  1  1|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page   5                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |             X                                               X        X   |      3     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectopic Pancreas                     |                                                          X               |      1     |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |    2        2                                                     2      |      3  2.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                         3                                            2   |      2  2.5|
      Basophilic Focus                     | X  X  X  X  X     X  X  X  X  X  X  X  X  X  X  X        X        X  X  X|     38     |
      Clear Cell Focus                     |                   X                                                     X|      4     |
      Congestion                           |                            2                                             |      4  1.8|
      Developmental Malformation           |                X                                                         |      1     |
      Eosinophilic Focus                   | X     X     X  X     X     X     X  X  X                 X        X      |     19     |
      Fibrosis                             |                                                                          |      1  1.0|
      Hepatodiaphragmatic Nodule           |                      X                       X              X           X|      9     |
      Inflammation, Chronic Active         |             1        1              1                                    |      9  1.3|
      Mitotic Alteration                   |                                                                          |      1  1.0|
      Mixed Cell Focus                     |                                                                      X   |      2     |
      Necrosis                             |                1           1                                             |      6  1.2|
      Pigmentation                         | 1                       1                                1               |      6  1.5|
      Tension Lipidosis                    |                                                                          |      3     |
      Vacuolization Cytoplasmic            |                2        2        1                 1     2               |     10  1.8|
      Bile Duct, Hyperplasia               | 1     1  1                       1  1     1              1     1  1      |     20  1.0|
      Centrilobular, Degeneration          |                                                          2               |      1  2.0|
      Centrilobular, Necrosis              |                                                       3                  |      1  3.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               | +        +                             +     +                 +         |   9        |
      Fat, Necrosis                        | 2        2                             2     2                 2         |      8  2.0|
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Atrophy                              | 1  1        1                 1           1                 1     1  1  1|     22  1.1|
      Cytoplasmic Alteration               |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperkeratosis                       |                                                       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   6                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Inflammation, Acute                  |                                                             2            |      1  2.0|
      Inflammation, Chronic Active         |                                                       2                  |      2  3.0|
      Ulcer                                |                         3                                   2            |      3  2.7|
      Epithelium, Hyperplasia, Squamous    |                         4  3                                             |      2  3.5|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |          1     4        2                                      4         |      6  2.8|
      Inflammation, Chronic Active         |                                                       3                  |      1  3.0|
      Ulcer                                |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cardiomyopathy                       | 1  1  1  1  1  2  1  1  1  1  1  1  2  2  2  1  2  1     1  1  1  1     1|     42  1.2|
      Inflammation, Chronic Active         |                                                                          |      1  1.0|
      Mineralization                       |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Adrenal Cortical Nodule    |                                                                          |      1  2.0|
      Hematopoietic Cell Proliferation     |                1                                                         |      1  1.0|
      Hemorrhage                           |                               2                                          |      1  2.0|
      Hyperplasia                          |    1  2  1                    2                                   2  1  1|     11  1.3|
      Vacuolization Cytoplasmic            |                                  1                    2                  |      6  1.8|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |          2                             1                       1         |      5  1.6|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |                                                       2                  |      1  2.0|
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pars Distalis, Angiectasis           |    3  3  3                                                  2            |     11  2.7|
      Pars Distalis, Cyst                  | 1        2  3  2                 2                 1              2     2|     16  2.0|
      Pars Distalis, Hemorrhage            |                2                                                         |      1  2.0|
      Pars Distalis, Hyperplasia           | 2  3                          4  4  4  4           1        1  4  2      |     22  2.5|
      Pars Intermedia, Hyperplasia         |                                     2                                    |      1  2.0|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  | 1                             1        3           1     2               |     16  1.3|
      Follicular Cell, Hyperplasia         | 1                                                                        |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page   7                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Hyperplasia                          |                                                                          |      1  1.0|
      Inflammation, Acute                  |                                                                          |      1  2.0|
      Inflammation, Chronic                |                                              1  1                        |      3  1.0|
      Inflammation, Chronic Active         |                                                                          |      1  3.0|
      Duct, Ectasia                        |                                                                1         |      3  1.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      1  2.0|
      Cyst                                 |                                                       2           4      |      3  2.7|
      Inflammation, Chronic                |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Cystic                  |          1                    1                                1     1   |      6  1.0|
      Necrosis                             |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Depletion Cellular                   |                         3                                                |      1  3.0|
      Fibrosis                             |                                                                          |      1  1.0|
      Hyperplasia                          | 2              2                                                         |      3  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                    +        +  +         |   7        |
      Iliac, Congestion                    |                                                             2            |      2  2.0|
      Mediastinal, Congestion              |                                                    2           2         |      3  2.0|
      Mediastinal, Pigmentation            |                                                    3                     |      1  3.0|
      Renal, Congestion                    |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Atrophy                              |                                                                          |      1  1.0|
      Ectasia                              |                                        1                                 |      3  1.3|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Hyperplasia, Plasma Cell             |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  49        |
      Congestion                           |                                                                          |      2  2.0|
      Hemorrhage                           |                         2                                                |      1  2.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      1  3.0|
      Fibrosis                             |                                                             2            |      2  2.0|
      Hematopoietic Cell Proliferation     |                4                                                         |      2  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectopic Parathyroid Gland            |                                        X                          X      |      2     |
      Inflammation, Acute                  |                                                                          |      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   8                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                         2                                3               |      3  2.7|
      Hyperplasia                          |    1  2                                                                  |      5  2.2|
      Duct, Dilatation                     |       4           4        1     1        3                          2   |     13  2.2|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                               2           4                              |      2  3.0|
      Inflammation, Acute                  |                                                                          |      1  2.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
      Inflammation, Chronic Active         |                               3           2                              |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Osteopetrosis                        |                   1                                         2  2        3|      9  2.6|
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      1  2.0|
      Infiltration Cellular, Histiocyte    |       1                          1                             1  1     1|     13  1.0|
      Inflammation, Chronic                |                               2  1              1  1                     |      9  1.2|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  2.0|
      Inflammation, Chronic                |             1                                      1                     |      2  1.0|
      Inflammation, Chronic Active         |    1  1  1                    3  3  2  2     1  2                        |     15  1.7|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic Active                  |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   1        |
      Inflammation, Chronic                |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 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   9                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      2  2.0|
      Mineralization                       |                                        1                                 |      3  1.3|
      Nephropathy                          | 1  1  1  1        1  1  2  1  1  1  1        1  2  1  4  1  1  1  1  2  1|     41  1.3|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : 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: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |          X                                                               |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |                            X                                             |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                       4                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +|             
      Hyperplasia, Lymphoid                |                2                                                         |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                              2                           |             
      Basophilic Focus                     | X        X     X  X  X     X  X              X                 X     X   |             
      Clear Cell Focus                     |                X     X     X           X                       X         |             
      Congestion                           |                                                                          |             
      Developmental Malformation           |                      X                       X                           |             
      Eosinophilic Focus                   | X        X     X  X  X     X  X        X           X           X     X  X|             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                           2                              |             
      Hemorrhage                           |                                                                          |             
      Hepatodiaphragmatic Nodule           |    X  X        X                 X                    X                  |             
      Inflammation, Chronic Active         |                                                                          |             
      Mixed Cell Focus                     |                      X           X                                       |             
      Necrosis                             |                                           3                              |             
      Pigmentation                         |                1                                                         |             
      Tension Lipidosis                    |                                  X                                       |             
      Vacuolization Cytoplasmic            |                                        1           1                     |             
      Bile Duct, Hyperplasia               | 1  1  1  1  2     1        1  1        1     1  1  1  1  2           1   |             
      Centrilobular, Cytomegaly            |                                                                          |             
      Centrilobular, Degeneration          |                                     2     3                              |             
      Centrilobular, Necrosis              |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +              +        +              +     +              +         |             
      Fat, Necrosis                        |    2              2        2                    2              2         |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                                       +                  |             
      Pharyngeal, Inflammation, Acute      |                                                       3                  |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              | 1     1           1        1     2                          2        1  1|             
      Ectopic Liver                        |                                              X                 X         |             
      Hyperplasia                          |                               4                                4         |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                       2                  |             
      Cytoplasmic Alteration               |                                                    1                     |             
      Inflammation, Chronic                |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  11                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
      Ulcer                                |                                     3     2                       3      |             
      Epithelium, Hyperplasia, Squamous    |                         2                             1                  |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |    1                    4           3     2                              |             
      Ulcer                                |                                                       4                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1     1  1        1  1  1  2  2  1     1        1  2  2  1  1  1     1  1|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Cyst                                 |                                                                          |             
      Hyperplasia                          |                                        1                             2  1|             
      Vacuolization Cytoplasmic            | 3                       1  1                 2     2              3      |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    4              1     1           2                       1            |             
      Necrosis                             |                                                       3                  |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                         2                       3     1  3        3     4|             
      Pars Distalis, Cyst                  |             2     2                    3  2     2  2           2  2      |             
      Pars Distalis, Ectasia               |       3                                                                  |             
      Pars Distalis, Hyperplasia           | 3           4           4  3     1  4  1     4                 2  3  2   |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ultimobranchial Cyst                 |    2                                               2                     |             
      C-Cell, Hyperplasia                  | 1     1  1     1                    1        1  1                        |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          2                 3                                             |             
      Inflammation, Acute                  | 3                                                                        |             
      Inflammation, Chronic                |       1                                                                  |             
      Inflammation, Chronic Active         |          2                                                               |             
      Duct, Ectasia                        |          2     3                                               3         |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | 4        2                                            4                  |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  12                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Hyperplasia                          |                                        2                                 |             
      Bilateral, Cyst                      |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Cyst                                 |                                                                          |             
      Dilatation                           |                                           4                              |             
      Hemorrhage                           |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hyperplasia                          |                                  1        3                              |             
      Hyperplasia, Reticulum Cell          |                                        3                                 |             
      Myeloid Cell, Hyperplasia            |                                           4                              |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +        +           +           +                       +     +     +|             
      Mediastinal, Congestion              |                                                                          |             
      Pancreatic, Pigmentation             |                                                                          |             
      Renal, Congestion                    |                                                                          |             
      Renal, Ectasia                       |                                                                         2|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                      1                                                   |             
      Ectasia                              |                   1              2                             1         |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Infiltration Cellular, Plasma Cell   |                                                       3                  |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                           3                              |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |             2                                         1                  |             
      Hematopoietic Cell Proliferation     |                                           4                              |             
      Hemorrhage                           |                                              2                           |             
      Metaplasia, Osseous                  |                                                                          |             
      Necrosis                             |                                                       1                  |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectopic Parathyroid Gland            |                                                                          |             
      Fibrosis                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                   4                                2              2      |             
      Hyperplasia                          |                                                                          |             
      Duct, Dilatation                     | 2     1  1                                2     3  1  1                  |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  13                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia, Squamous                |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
      Subcutaneous Tissue, Fibrosis        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Osteopetrosis                        |             2     2                                   3     2        3   |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                           +                              |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Histiocyte    |                   1                    1     1  1                        |             
      Inflammation, Chronic                |                         3                    1           1               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                         1                                                |             
      Inflammation, Chronic Active         | 3           1     3                                      3  1           1|             
      Nasolacrimal Duct, Cyst              |                                  2                                       |             
                                            __________________________________________________________________________|             
   Pleura                                  |                                     +                                    |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                  +                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hydronephrosis                       |                                           3                              |             
      Nephropathy                          | 1     2  1  1  1  1     1  1  1  1     2     1  1  1  1  1  2  1  1  1  3|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Inflammation, Chronic                |                                                    1           1         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  14                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                                        X           X                     |      3     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                                        X                                 |      2     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ulcer                                |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia, Lymphoid                |                                                          1               |      2  1.5|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                             2            |      2  2.0|
      Basophilic Focus                     |    X  X  X  X  X  X  X  X        X     X  X  X     X  X  X  X     X  X   |     28     |
      Clear Cell Focus                     |       X  X  X  X                                                         |      9     |
      Congestion                           |                                                             2            |      1  2.0|
      Developmental Malformation           |                                                                          |      2     |
      Eosinophilic Focus                   | X  X  X  X  X     X     X        X           X        X           X     X|     24     |
      Fibrosis                             |                            1                                             |      1  1.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Hemorrhage                           |                         2                                                |      1  2.0|
      Hepatodiaphragmatic Nodule           |       X        X           X                                             |      8     |
      Inflammation, Chronic Active         |                                                       1                  |      1  1.0|
      Mixed Cell Focus                     |                                              X                 X         |      4     |
      Necrosis                             |                                                                          |      1  3.0|
      Pigmentation                         |                            2                                             |      2  1.5|
      Tension Lipidosis                    |                                                                          |      1     |
      Vacuolization Cytoplasmic            |    1                                         1        1  1        1      |      7  1.0|
      Bile Duct, Hyperplasia               | 1  1  1     1     1  1  1        1  1  1     1        1  1  1            |     29  1.1|
      Centrilobular, Cytomegaly            |                                                                      1   |      1  1.0|
      Centrilobular, Degeneration          |                                                                          |      2  2.5|
      Centrilobular, Necrosis              |                         2  1                                             |      2  1.5|
                                            __________________________________________________________________________|____________|
   Mesentery                               |             +              +                 +                 +        +|  11        |
      Fat, Necrosis                        |             2                                2                 2        2|      9  2.0|
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   1        |
      Pharyngeal, Inflammation, Acute      |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |    1        1  1     3                 2  1                              |     14  1.4|
      Ectopic Liver                        |                                                                          |      2     |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  15                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Hyperplasia                          |                            1                                             |      3  3.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                     1                                    |      2  1.5|
      Cytoplasmic Alteration               |                                                                          |      1  1.0|
      Inflammation, Chronic                |                                              1                           |      2  2.0|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |       3                                                                  |      1  3.0|
      Ulcer                                |                                                                          |      3  2.7|
      Epithelium, Hyperplasia, Squamous    |                                                                          |      2  1.5|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                         2  3  1                 1                       2|      9  2.1|
      Ulcer                                |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       | 2  1  1  1  1  1  1  1  1  1  1  1  2  1  2  1  1  1  1  1  1  1  1  1  1|     43  1.2|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                         4                                                |      1  4.0|
      Cyst                                 |                                                 3                        |      1  3.0|
      Hyperplasia                          | 2     1        1  1  2              1     2           1     1            |     12  1.3|
      Vacuolization Cytoplasmic            |             3                                                           1|      8  2.0|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                   2     1                                                |      7  1.7|
      Necrosis                             |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Angiectasis           | 3                          3                          1                  |      9  2.6|
      Pars Distalis, Cyst                  |    1        2  1  1                    2     1  3  1     2        2      |     18  1.8|
      Pars Distalis, Ectasia               |                                                                          |      1  3.0|
      Pars Distalis, Hyperplasia           |    1  1  2  1  1  2  3     4  1  3  1  3  4  2     2  1  2        1      |     29  2.3|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ultimobranchial Cyst                 |                                                                      1   |      3  1.7|
      C-Cell, Hyperplasia                  | 1     1              1  1        3  1     2     2        1           1   |     17  1.2|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  16                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |                                                                          |      2  2.5|
      Inflammation, Acute                  |                                                             2            |      2  2.5|
      Inflammation, Chronic                |                                                                          |      1  1.0|
      Inflammation, Chronic Active         |                                                                          |      1  2.0|
      Duct, Ectasia                        |          3        1                                                      |      5  2.4|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |       4     4                 4                          3               |      7  3.6|
      Hyperplasia                          |                                                                          |      1  2.0|
      Bilateral, Cyst                      |                                     4                                    |      1  4.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |          3                                                               |      1  3.0|
      Cyst                                 |       4                                                                  |      1  4.0|
      Dilatation                           |                                                                          |      1  4.0|
      Hemorrhage                           |                                                             3            |      1  3.0|
      Inflammation, Chronic                | 3                                                                        |      1  3.0|
      Inflammation, Chronic Active         |       3                                                                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                      1                                                   |      1  1.0|
      Hyperplasia                          |                         1                                               1|      4  1.5|
      Hyperplasia, Reticulum Cell          |                                                                          |      1  3.0|
      Myeloid Cell, Hyperplasia            |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                            +                       +                     |   9        |
      Mediastinal, Congestion              |                            1                                             |      1  1.0|
      Pancreatic, Pigmentation             |                                                    2                     |      1  2.0|
      Renal, Congestion                    |                            1                                             |      1  1.0|
      Renal, Ectasia                       |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      1  1.0|
      Ectasia                              |                                                 3                        |      4  1.8|
      Hyperplasia, Lymphoid                |                                                    2                     |      1  2.0|
      Infiltration Cellular, Plasma Cell   |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                            2                                             |      2  2.5|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                                                 3                        |      3  2.0|
      Hematopoietic Cell Proliferation     |                         1  1                                            1|      4  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  17                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Hemorrhage                           |                                                                         2|      2  2.0|
      Metaplasia, Osseous                  |                               2                                          |      1  2.0|
      Necrosis                             |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectopic Parathyroid Gland            |             X                                                            |      1     |
      Fibrosis                             |                               2                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |          2                                   2                           |      5  2.4|
      Hyperplasia                          |                                           2                          1   |      2  1.5|
      Duct, Dilatation                     |       1                                                        1         |      9  1.4|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                | 2                                                                        |      1  2.0|
      Inflammation, Chronic Active         |                                                                      2   |      1  2.0|
      Subcutaneous Tissue, Fibrosis        | 2                                                                        |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Osteopetrosis                        |       1  1     3        2                       1     1  1               |     12  1.8|
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                 1                        |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Histiocyte    |    1     1  1                    1           1                       1   |     10  1.0|
      Inflammation, Chronic                |                1     1  2                       1                 1      |      8  1.4|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  1.0|
      Inflammation, Chronic Active         |    1           1     1                 3  1  1  1  3                 3   |     15  1.8|
      Nasolacrimal Duct, Cyst              |                                                                1         |      2  1.5|
                                            __________________________________________________________________________|____________|
   Pleura                                  |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                          |   1        |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  18                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hydronephrosis                       |                            4                                             |      2  3.5|
      Nephropathy                          | 1     1  1  1  1  2  1  1        1  3  1  2  1  1  1  1  1  1  2  3  2   |     42  1.3|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                         2                                                |      1  2.0|
      Inflammation, Chronic                |                                                                      1   |      3  1.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  19                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 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|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                         1                                                |             
      Parasite Metazoan                    |                               X                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |             X                                                            |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
      Parasite Metazoan                    |                                                             X            |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                         1  1                                             |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |          1                 2                                             |             
      Basophilic Focus                     |                   X        X  X     X  X        X                        |             
      Clear Cell Focus                     |          X                 X  X                 X  X     X  X     X      |             
      Congestion                           |                                                                          |             
      Developmental Malformation           |                                                                          |             
      Eosinophilic Focus                   |                      X  X  X  X           X  X  X        X  X     X      |             
      Hematopoietic Cell Proliferation     |       2                                                                  |             
      Hemorrhage                           |                                                                          |             
      Hepatodiaphragmatic Nodule           |                                     X              X                     |             
      Inflammation, Chronic Active         |                      1                                                   |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |       1                                                                  |             
      Pigmentation                         |       1                                                                  |             
      Vacuolization Cytoplasmic            |       4           1           1           2              1  1            |             
      Bile Duct, Hyperplasia               | 1  1  1  1  1  1  1  1  1     1     1  1  1  1        1  1  1     1  1  1|             
      Centrilobular, Cytomegaly            |                   1                                               1      |             
      Centrilobular, Degeneration          |                                                                          |             
      Centrilobular, Necrosis              |                                                                2         |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                  +        +                 +        +   |             
      Ectopic Spleen                       |                                                                          |             
      Fat, Necrosis                        |                                  2        2                 2        2   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |          2     1                    3                 1           1      |             
      Ectopic Liver                        |                                           X                              |             
      Hyperplasia                          |                                              3                           |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                               2                             1            |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  20                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 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|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Fibrosis                             |                                                                          |             
      Inflammation, Acute                  |                                                          1               |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Chronic Active         |                                                                      3  4|             
      Ulcer                                |                                                                          |             
      Epithelium, Hyperplasia, Squamous    |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                       3        2         |             
      Mineralization                       |                                           2                              |             
      Ulcer                                |    3  4                                                                  |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Epithelium, Hyperplasia              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1  1  1     1     1  1  1  1     1  1  1  1  1  2  1  1  1  1  1  1  1   |             
      Thrombosis                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Hyperplasia                          |                   1                       2                       1      |             
      Vacuolization Cytoplasmic            |       1              2     1        1                                    |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                  2           3                           |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        1                                 |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pigmentation                         |                                                                          |             
      Pars Distalis, Angiectasis           |                               3  3     4  2  2  2                 3      |             
      Pars Distalis, Cyst                  |    2  2                 2  2     3  2                    2  2  1  3      |             
      Pars Distalis, Hyperplasia           |    2           4           2  3     2  4     1  3  1     2        4      |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |          2                       1        3        2  1        2  4      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Inflammation, Chronic                |                   1  1                          1                        |             
      Inflammation, Chronic Active         |       2                                                                 4|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  21                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 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|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Bilateral, Inflammation, Acute       |                                                                          |             
      Duct, Ectasia                        |       3        3                    3                                    |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |    3                                                              4      |             
      Pigmentation                         |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Developmental Malformation           |                                                                          |             
      Dilatation                           |                                                                          |             
      Hyperplasia, Cystic                  |                            2                          1        1         |             
      Metaplasia, Squamous                 |                                                                          |             
      Cervix, Hypertrophy                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |       4                                                                  |             
      Necrosis                             |                                                                          |             
      Erythroid Cell, Hyperplasia          |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +                             +                                   +  +|             
      Mediastinal, Congestion              |                                                                          |             
      Mediastinal, Hyperplasia, Lymphoid   |                                                                          |             
      Pancreatic, Congestion               |                                                                          |             
      Renal, Congestion                    |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Ectasia                              | 1  2           1                             1  1  1     1               |             
      Necrosis                             |       2                                                                  |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Ectasia                              |                   3                                      1  1            |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Fibrosis                             |    2  4                                                                 1|             
      Necrosis                             |                                  3                                       |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Cyst                                 |                                                          1               |             
      Ectopic Parathyroid Gland            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                              3                           |             
      Hyperplasia                          |                                           2              3               |             
      Inflammation, Chronic Active         |       4                                                                  |             
      Duct, Dilatation                     | 2           2  1                    1  1                             2  4|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  22                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 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|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis                       |       4                                                                  |             
      Hyperplasia, Squamous                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Osteopetrosis                        |       1                                      3        3                  |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Histiocyte    |                            1                                1  1         |             
      Inflammation, Chronic                |                               1              1  2                        |             
      Bronchiole, Alveolus, Hyperplasia    |                                                    4                     |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Inflammation, Chronic                |                   1  1  1                                                |             
      Inflammation, Chronic Active         | 1                             1              2  1     1              1  3|             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Chronic Active                  |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                             +            |             
      Hemorrhage                           |                                                             2            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |             2                                                            |             
      Cyst                                 |                                              1                           |             
      Mineralization                       |                                        1        1                       1|             
      Nephropathy                          |    1  1  2     1     1  1     1  1        1  2     2  1     1  1  1     1|             
      Pigmentation                         |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  23                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                                          |      1  1.0|
      Parasite Metazoan                    |                                                    X     X               |      3     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |    3                                                                     |      1  3.0|
      Parasite Metazoan                    |                                                                          |      1     |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |             3                                                            |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                                          |      2  1.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                              2                           |      3  1.7|
      Basophilic Focus                     |       X           X                       X              X           X   |     11     |
      Clear Cell Focus                     |       X                                   X              X               |     11     |
      Congestion                           |                                        2     2                 3         |      3  2.3|
      Developmental Malformation           |                                  X                                       |      1     |
      Eosinophilic Focus                   | X     X  X        X              X        X  X     X     X  X        X  X|     22     |
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Hemorrhage                           |                                        3                                 |      1  3.0|
      Hepatodiaphragmatic Nodule           | X                                                                        |      3     |
      Inflammation, Chronic Active         |                                                                      1   |      2  1.0|
      Mixed Cell Focus                     |                                  X                                       |      1     |
      Necrosis                             |                                                                          |      1  1.0|
      Pigmentation                         |             3                       3  4     1              2            |      6  2.3|
      Vacuolization Cytoplasmic            |                                        4           1                    1|      9  1.8|
      Bile Duct, Hyperplasia               | 1  1  1  1              2  1  1     1        1  1  1     1  1           1|     34  1.0|
      Centrilobular, Cytomegaly            | 1                                                           1            |      4  1.0|
      Centrilobular, Degeneration          |             1                                               2            |      2  1.5|
      Centrilobular, Necrosis              |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                +                                      +  +               |   7        |
      Ectopic Spleen                       |                X                                                         |      1     |
      Fat, Necrosis                        |                                                       2  2               |      6  2.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |    1  1        1  1        1  1        1                             1   |     13  1.2|
      Ectopic Liver                        |       X                                                                  |      2     |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  24                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Hyperplasia                          |                                                                      2   |      2  2.5|
      Inflammation, Chronic                |             3                                                            |      1  3.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |          1                                                               |      3  1.3|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                            2                                             |      1  2.0|
      Inflammation, Acute                  |                                                                          |      1  1.0|
      Inflammation, Chronic                |                                                 2                        |      1  2.0|
      Inflammation, Chronic Active         |                                                                          |      2  3.5|
      Ulcer                                |    3           3              3        3                                 |      4  3.0|
      Epithelium, Hyperplasia, Squamous    |                                                 3                 2      |      2  2.5|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |    3        4  3           1  2        2              2                  |      9  2.4|
      Mineralization                       |                                     1                                    |      2  1.5|
      Ulcer                                |             2                                                            |      3  3.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                             +            |   1        |
      Epithelium, Hyperplasia              |                                                             4            |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |    1  1     2  1  1     1  1  1  1  2  1  1  2  2  1  1  1  2  2  1  1  1|     43  1.2|
      Thrombosis                           |                2                    2                                    |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                            4                                             |      1  4.0|
      Hyperplasia                          | 2                             1  2                       1           1  1|      9  1.3|
      Vacuolization Cytoplasmic            |                3                       2                                 |      6  1.7|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       1           1  1              2  4        2                        |      8  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pigmentation                         |                2                                                         |      1  2.0|
      Pars Distalis, Angiectasis           |    2  2           2        4                                            2|     12  2.6|
      Pars Distalis, Cyst                  |    2     2  3           3     2  2  2  2                          2  1   |     20  2.1|
      Pars Distalis, Hyperplasia           |    4  1  2  1           4     2     2                 1           2  2   |     21  2.3|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : 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: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      C-Cell, Hyperplasia                  | 1        1        1  1           2        4                              |     13  1.9|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                         3|      1  3.0|
      Inflammation, Chronic                | 1                                1                                       |      5  1.0|
      Inflammation, Chronic Active         |                                                                          |      2  3.0|
      Bilateral, Inflammation, Acute       |                                                                      4   |      1  4.0|
      Duct, Ectasia                        |                                                                         3|      4  3.0|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                   2  3                                                   |      4  3.0|
      Pigmentation                         |             2                                                            |      1  2.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Developmental Malformation           |       X                                                                  |      1     |
      Dilatation                           |                                                 4                        |      1  4.0|
      Hyperplasia, Cystic                  |                1           1                                             |      5  1.2|
      Metaplasia, Squamous                 |                                                 2                        |      1  2.0|
      Cervix, Hypertrophy                  |                                           4                              |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Depletion Cellular                   | 2                                                                        |      2  3.0|
      Necrosis                             |    2                                                                     |      1  2.0|
      Erythroid Cell, Hyperplasia          |             1                                                            |      1  1.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |    +  +  +     +        +  +  +     +  +        +     +                  |  15        |
      Mediastinal, Congestion              |          2                    3     2  3                                 |      4  2.5|
      Mediastinal, Hyperplasia, Lymphoid   |       2                                                                  |      1  2.0|
      Pancreatic, Congestion               |                                        3                                 |      1  3.0|
      Renal, Congestion                    |                               2                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                        2                                 |      1  2.0|
      Ectasia                              |       1           1                                                      |      9  1.1|
      Necrosis                             |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                               2     2  2                                 |      3  2.0|
      Ectasia                              |          2                                                               |      4  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  26                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                        3                       4         |      2  3.5|
      Fibrosis                             |                                                                          |      3  2.3|
      Necrosis                             |                               4                                          |      2  3.5|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                3         |      1  3.0|
      Cyst                                 |                                                                          |      1  1.0|
      Ectopic Parathyroid Gland            |                                                                      X   |      1     |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                                                                          |      1  3.0|
      Hyperplasia                          |       3                             1              2        3            |      6  2.3|
      Inflammation, Chronic Active         |                                                                          |      1  4.0|
      Duct, Dilatation                     | 1     2              1                    1        4              1      |     13  1.8|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperkeratosis                       | 4                                                                        |      2  4.0|
      Hyperplasia, Squamous                | 4                                                                        |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Osteopetrosis                        |          3        2        4              4           1        2  1      |     10  2.4|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Histiocyte    | 1                             1     2     1  1           1               |      9  1.1|
      Inflammation, Chronic                |       1     1                                                  1         |      6  1.2|
      Bronchiole, Alveolus, Hyperplasia    |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                3         |      1  3.0|
      Inflammation, Chronic                |                                                                          |      3  1.0|
      Inflammation, Chronic Active         |    2        2  1  3                    4        1        3           1  1|     16  1.8|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Chronic Active                  |                                              2                           |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  27                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   1        |
      Hemorrhage                           |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                                                          |      1  2.0|
      Cyst                                 |                                                                          |      1  1.0|
      Mineralization                       |                                     2                                    |      4  1.3|
      Nephropathy                          | 2     2  1  1     2     2  1  1  1  2     2  2  3  1     1  1     1  1  1|     35  1.3|
      Pigmentation                         |             3     2                                                      |      2  2.5|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                                         1|      1  1.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  28                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |                      X                                                   |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                      2        2           2        2                     |             
      Inflammation, Chronic Active         |                                              4                           |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                      1   |             
      Clear Cell Focus                     |                X     X     X  X  X     X  X           X        X  X  X   |             
      Congestion                           |                   2     2                                                |             
      Eosinophilic Focus                   | X        X  X  X     X                                X  X  X  2  X  X   |             
      Hematopoietic Cell Proliferation     |                                                          1               |             
      Hepatodiaphragmatic Nodule           |                                                          X           X   |             
      Inflammation, Chronic Active         |          1                                            1                  |             
      Mitotic Alteration                   |                                                                          |             
      Mixed Cell Focus                     | X     X                                               X  X        X      |             
      Pigmentation                         | 2     1        1           1           1  1        2  1        3  3      |             
      Vacuolization Cytoplasmic            | 2     3  3     1           2     1     1  1        2     1     2     1   |             
      Bile Duct, Hyperplasia               | 1  1  1  1  1  1     1     1  1     1        1  1  1        1  1  1  1   |             
      Capsule, Inflammation, Chronic       |                                                                          |             
      Centrilobular, Cytomegaly            | 1        2     1           1  1  2     2  1        1     1        1      |             
      Centrilobular, Degeneration          |                            1                                   2  1      |             
                                            __________________________________________________________________________|             
   Mesentery                               |             +                    +           +                 +  +     +|             
      Inflammation                         |                                                                          |             
      Fat, Necrosis                        |                                  2           2                 2  2     2|             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                           +                       +      |             
      Pharyngeal, Hyperplasia              |                                           3                              |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |          1  1  1              1           2  2  1                    1   |             
      Ectopic Liver                        |                            X                                             |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                       1                  |             
      Cytoplasmic Alteration               |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
      Ulcer                                |                                                                         3|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  29                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Epithelium, Hyperplasia, Squamous    |                                                                         3|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |    1                                         4                           |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Epithelium, Hyperplasia              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |    1  2  1  1     1  1     1     1  1     1  1  1  1  1  1  1  1  1  1  1|             
      Thrombosis                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Cyst                                 |                                                                          |             
      Hyperplasia                          |                                        4                          1      |             
      Vacuolization Cytoplasmic            |                                                    1                    2|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                              2                           |             
      Pars Distalis, Cyst                  |             3        1        2                          3           2   |             
      Pars Distalis, Hyperplasia           |    1                          2     1  1                 2  1        2   |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ultimobranchial Cyst                 |    2                                                                     |             
      C-Cell, Hyperplasia                  |             1        2     3              1                 1  4         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Inflammation, Chronic                |    1  2                                                                  |             
      Inflammation, Chronic Active         |                                                                          |             
      Vacuolization Cytoplasmic            |                                                                          |             
      Duct, Ectasia                        |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       2                                                                  |             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  30                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Bilateral, Cyst                      |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Dilatation                           |                3        2                                                |             
      Hemorrhage                           |                                                                          |             
      Hyperplasia, Cystic                  | 4     1                                         1  2     2               |             
      Hyperplasia                          |                                        2                                 |             
      Inflammation, Acute                  | 4                                                                        |             
      Inflammation, Chronic                |                                                                          |             
      Necrosis                             |                                                                          |             
      Cervix, Inflammation, Chronic        |                                                                          |             
                                            __________________________________________________________________________|             
   Vagina                                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                     2                                    |             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +     +  +                                +  +        +              +|             
      Iliac, Ectasia                       |                                                          2               |             
      Mediastinal, Congestion              |                                                                          |             
      Mediastinal, Pigmentation            |                                                                          |             
      Renal, Ectasia                       |                                                                          |             
      Renal, Hyperplasia, Lymphoid         |          1                                                               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |                                                          1               |             
      Edema                                |                                     4                                    |             
      Hyperplasia, Lymphoid                |          3                                                               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                            1                       2                     |             
      Inflammation, Acute                  |                                     3                                    |             
      Inflammation, Chronic                |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Fibrosis                             |             2              1                                            2|             
      Hematopoietic Cell Proliferation     |                                                          3               |             
      Necrosis                             |                                                                         2|             
      Pigmentation                         |                                                                          |             
      Capsule, Inflammation, Chronic       |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectopic Parathyroid Gland            |                                                                          |             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  31                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Hyperplasia                          |                                                                          |             
      Duct, Dilatation                     |    1     2                             1     3  2                        |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Osteopetrosis                        |                                                                2         |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                   4  1                                                   |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                             1            |             
      Infiltration Cellular, Histiocyte    | 1           1              1  1     1                                    |             
      Inflammation, Chronic                | 1              1     3                                      1        1   |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Inflammation, Chronic Active         | 3  1  1  2  2        1              3                 1  1     1     2   |             
      Respiratory Epithelium, Hyperplasia  |                                        3                                 |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                        +  +                              |             
      Hemorrhage                           |                                        2  3                              |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accumulation, Hyaline Droplet        |                                                                          |             
      Inflammation, Acute                  |                                     3                                    |             
      Mineralization                       | 1  1                                            1           1            |             
      Nephropathy                          | 1  1  1  3  1  1     1  1  1     1     1  1  1     2  2        1  1  1   |             
      Pigmentation                         |                      1                                                   |             
      Renal Tubule, Hyperplasia            |                   2                                                      |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  32                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                            X                                             |      1     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                                              X                           |      2     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                                   3      |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                     2                                    |      5  2.0|
      Inflammation, Chronic Active         |                                                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                                   1      |      2  1.0|
      Clear Cell Focus                     |    X                                         X     X        X           X|     16     |
      Congestion                           |                                                                          |      2  2.0|
      Eosinophilic Focus                   |                   X                       X              X              X|     15  2.0|
      Hematopoietic Cell Proliferation     |                                                 1                        |      2  1.0|
      Hepatodiaphragmatic Nodule           |                                                                   X      |      3     |
      Inflammation, Chronic Active         |                                                    1           1         |      4  1.0|
      Mitotic Alteration                   |                                              2                           |      1  2.0|
      Mixed Cell Focus                     |                                                                          |      5     |
      Pigmentation                         |    2        1                                2              2  1  2     1|     17  1.6|
      Vacuolization Cytoplasmic            |                   1        1                       1        2  2        1|     18  1.6|
      Bile Duct, Hyperplasia               |    1  1           1     1           1  1     1  1        1     1     1  1|     29  1.0|
      Capsule, Inflammation, Chronic       |                                           2                       2      |      2  2.0|
      Centrilobular, Cytomegaly            |    2        2     1        2                    2  1        2  1        1|     20  1.4|
      Centrilobular, Degeneration          |    1                                         1                 1        1|      7  1.1|
                                            __________________________________________________________________________|____________|
   Mesentery                               |          +        +     +                       +     +           +      |  12        |
      Inflammation                         |                                                                   3      |      1  3.0|
      Fat, Necrosis                        |          1        2     2                       2     2           2      |     11  1.9|
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   2        |
      Pharyngeal, Hyperplasia              |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |       1     1              1                 1                       1  1|     14  1.1|
      Ectopic Liver                        |             X                                         X                  |      3     |
      Inflammation, Chronic                |                                              2                    3      |      2  2.5|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                                          |      1  1.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  33                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
      Cytoplasmic Alteration               |                                                 1                        |      1  1.0|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                                   4      |      1  4.0|
      Inflammation, Chronic Active         |                                  3                                       |      1  3.0|
      Ulcer                                |                                  2                    2           3      |      4  2.5|
      Epithelium, Hyperplasia, Squamous    |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                1     2              4                 2  1               |      7  2.1|
      Inflammation, Chronic                |                                                                   4      |      1  4.0|
                                            __________________________________________________________________________|____________|
   Tongue                                  |                +                                   +                     |   2        |
      Epithelium, Hyperplasia              |                                                    4                     |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |    1  1     1     1  1     1     1     1     1  1  1  2  1     1     1  1|     36  1.1|
      Thrombosis                           | 3                                                                        |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                                        4                                 |      1  4.0|
      Cyst                                 |                                                 3                        |      1  3.0|
      Hyperplasia                          |             1                                1     1     2               |      6  1.7|
      Vacuolization Cytoplasmic            |                                                          1               |      3  1.3|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          | 1                                   3                                    |      2  2.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                       1                  |      1  1.0|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Angiectasis           |                                                       2           1  2   |      4  1.8|
      Pars Distalis, Cyst                  |                      2                 2                             2   |      8  2.1|
      Pars Distalis, Hyperplasia           |    1  2              2     4           2     3     4  4  3           2  1|     18  2.1|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ultimobranchial Cyst                 |                                                                          |      1  2.0|
      C-Cell, Hyperplasia                  |    1                                   1     1              1            |     10  1.6|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 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  34                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                                          3              2|      2  2.5|
      Inflammation, Chronic                |                                                                          |      2  1.5|
      Inflammation, Chronic Active         |                                           1                              |      1  1.0|
      Vacuolization Cytoplasmic            |                                                    1                     |      1  1.0|
      Duct, Ectasia                        |    2                                                     3               |      2  2.5|
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |             1                                                            |      2  1.5|
      Inflammation, Chronic                |                                                                   3      |      1  3.0|
      Bilateral, Cyst                      |       4           4                                                      |      2  4.0|
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                2                                                         |      1  2.0|
      Dilatation                           |                                                                          |      2  2.5|
      Hemorrhage                           |                                           3                              |      1  3.0|
      Hyperplasia, Cystic                  |                            1                                   1         |      7  1.7|
      Hyperplasia                          |                                                                          |      1  2.0|
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                   4      |      1  4.0|
      Necrosis                             |                                              4                           |      1  4.0|
      Cervix, Inflammation, Chronic        |                                  3                                       |      1  3.0|
                                            __________________________________________________________________________|____________|
   Vagina                                  |                      +                                                   |   1        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Depletion Cellular                   |                                     2                                    |      2  2.0|
      Hyperplasia                          |                                                 2                        |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +     +  +     +        +     +  +  +  +        +        +           +   |  19        |
      Iliac, Ectasia                       |                                                 2                        |      2  2.0|
      Mediastinal, Congestion              | 1                                                                        |      1  1.0|
      Mediastinal, Pigmentation            |                                     2                                    |      1  2.0|
      Renal, Ectasia                       |                                                          1               |      1  1.0|
      Renal, Hyperplasia, Lymphoid         |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectasia                              |                                                                         1|      2  1.0|
      Edema                                |                                                                          |      1  4.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                                          |      2  1.5|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  35                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Inflammation, Acute                  |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                                                   3      |      1  3.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                 2                        |      1  2.0|
      Fibrosis                             | 3                                                                        |      4  2.0|
      Hematopoietic Cell Proliferation     |                                                 3                        |      2  3.0|
      Necrosis                             |                                                                          |      1  2.0|
      Pigmentation                         |                                                                   2      |      1  2.0|
      Capsule, Inflammation, Chronic       |                                                                   1      |      1  1.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectopic Parathyroid Gland            | X     X                                                                  |      2     |
      Inflammation, Chronic                |                                                                   2      |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       2                             3           1     2        2         |      5  2.0|
      Duct, Dilatation                     |    1  2        1        1              1     1  2     1                  |     13  1.5|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                              3                           |      1  3.0|
      Inflammation, Acute                  |                                              2                           |      1  2.0|
      Inflammation, Chronic Active         |                                                                   3      |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Osteopetrosis                        |       1                             2                          3  1      |      5  1.8|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  1.0|
      Infiltration Cellular, Histiocyte    |             1                       1                    1  1     1     1|     11  1.0|
      Inflammation, Chronic                |       2                                1        1                        |      8  1.4|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                         3                                                |      1  3.0|
      Inflammation, Chronic Active         |             3     3        2     3        2        1     1        2      |     19  1.8|
      Respiratory Epithelium, Hyperplasia  |                                                                          |      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  36                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|      L     |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   2        |
      Hemorrhage                           |                                                                          |      2  2.5|
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                         +|   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accumulation, Hyaline Droplet        |                                                 3                        |      1  3.0|
      Inflammation, Acute                  |                                                                          |      1  3.0|
      Mineralization                       |                                                       1        1         |      6  1.0|
      Nephropathy                          | 1  2  2     3  1  1  1  1  2     2     1     2  1  2  1  1  1     1     1|     37  1.3|
      Pigmentation                         |                                                                          |      1  1.0|
      Renal Tubule, Hyperplasia            |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                                1  2      |      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  37                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 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|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |             X                       X                       X            |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |          X        X                                                      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |          4                                                               |             
      Ulcer                                |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hyperplasia, Lymphoid                |                                                 2        2        2  2   |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                      X                 X                             X   |             
      Clear Cell Focus                     |                                        X        X        X               |             
      Congestion                           |                                                                          |             
      Degeneration, Cystic                 |                                                 1              3         |             
      Eosinophilic Focus                   |                X     X                 X        X  X     X  X            |             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Hepatodiaphragmatic Nodule           | X                                                        X               |             
      Mixed Cell Focus                     | X                                                                        |             
      Necrosis                             |                                  1                                       |             
      Pigmentation                         | 1  1                                                                     |             
      Vacuolization Cytoplasmic            | 3                                      1                 1               |             
      Bile Duct, Hyperplasia               |    1  2  1  1  3  1  1  2  1  1     1  2  1  3  1  1  3  1  3  3  1  1   |             
      Centrilobular, Degeneration          |                                  2                                       |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +  +        +  +     +           +                             +  +   |             
      Cyst                                 |                                     2                                    |             
      Fat, Necrosis                        |    3  3        2  2     2                                         2  2   |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                            +                                             |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              | 3  1           2              1  1  1  2                                 |             
      Cytoplasmic Alteration               |                                                                          |             
      Hyperplasia                          |                                                             4            |             
      Inflammation, Chronic                |                                                                          |             
      Artery, Inflammation, Acute          |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         | 2                             4                                          |             
      Ulcer                                |                               3                                          |             
      Epithelium, Hyperplasia, Squamous    |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  38                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 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|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Erosion                              | 4        4  2     2     4  2              2  2        1        3  1      |             
      Inflammation, Chronic                |                                                                         2|             
      Ulcer                                | 2  2                                                                     |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                 +           +            |             
      Inflammation, Acute                  |                                                             2            |             
      Inflammation, Chronic Active         |                                                 3                        |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 2  2        2  2     1  1  2  2  1  3  2  2     1  2  1  2  2  1  1  1  1|             
      Mineralization                       |                                                                          |             
      Thrombosis                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Adrenal Cortical Nodule    |                                                    2                     |             
      Hyperplasia                          |                2     1                          1        1  1  2         |             
      Hypertrophy                          |                                                                          |             
      Vacuolization Cytoplasmic            |       3                                            2              1      |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |       4        2                                      3     3        3   |             
      Bilateral, Hyperplasia               |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |             2           2                 4                              |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Cyst                  |             2                                                            |             
      Pars Distalis, Hemorrhage            |                3                                                         |             
      Pars Distalis, Hyperplasia           |                   2  4              1  2  4  4  3  2     1     4         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ultimobranchial Cyst                 |                                                                         1|             
      C-Cell, Hyperplasia                  | 1                                1           1                 1         |             
      Follicle, Dilatation                 |                                                                          |             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |          2                                                               |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  39                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 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|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Hyperplasia                          |                   4                                2                     |             
      Inflammation, Acute                  |                   2                                                      |             
      Inflammation, Chronic                |                2                       1     1  1        1              2|             
      Inflammation, Chronic Active         |                         2                          2        1  1         |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                           2                              |             
      Inflammation, Acute                  | 4                                                                        |             
      Inflammation, Chronic                |                      1                                         3         |             
      Inflammation, Chronic Active         |    3        3  2        3  1  3  2  1  1  2  1  2  1  1  1  2            |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                | 2                                                                        |             
      Inflammation, Chronic Active         |                                              3                           |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              | 3                       2                                                |             
      Necrosis                             |       4                                                                  |             
      Bilateral, Interstitial Cell,        |                                                                          |             
          Hyperplasia                      |                               2  4                          1            |             
      Interstitial Cell, Hyperplasia       |                                                                   4     2|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                                2         |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +     +  +  +     +     +  +                 +              +     +     +|             
      Iliac, Hyperplasia, Lymphoid         |                                                                          |             
      Iliac, Infiltration Cellular, Plasma |                                                                          |             
          Cell                             | 4                                                                        |             
      Mediastinal, Hemorrhage              |                                                                          |             
      Renal, Congestion                    |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |    1                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |                      3                                                   |             
      Inflammation, Acute                  |                                                       2                  |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Fibrosis                             |                4                    3           3  2        2  3         |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Necrosis                             |                                                                   3     3|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Duct, Dilatation                     | 4  4                          2                 1           3  2         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  40                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 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|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Osteodystrophy               |                                                                3         |             
      Osteopetrosis                        |                                                    4                     |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hydrocephalus                        |                               2                                          |             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                              +                           |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                  2                                       |             
      Infiltration Cellular, Histiocyte    |                                                    1     1               |             
      Inflammation, Chronic                |                                                 1           1  1         |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |    3  2  1  2     2     2  2  2     1  1     2     1        2            |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Acute                           |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |          +                                                               |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                    2                     |             
      Developmental Malformation           |                                                                          |             
      Hydronephrosis                       |    2                                                                     |             
      Nephropathy                          | 4  3  1  2  2  3     3  2  1  2  1  3  3  1  3  2  3     2  3  2  2  2  1|             
      Artery, Inflammation, Acute          |                                                                          |             
      Artery, Inflammation, Chronic Active |                                                                          |             
      Renal Tubule, Hyperplasia            |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                | 2  2                                                                     |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  41                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |                   X                                                      |      4     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Parasite Metazoan                    |       X                                                     X            |      4     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Ulcer                                |                                                       4                  |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                         2                                                |      1  2.0|
      Hyperplasia, Lymphoid                |          2                       2                                       |      6  2.0|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     | X  X  X        X           X     X  X     X                    X         |     12     |
      Clear Cell Focus                     |          X           X     X              X                              |      7     |
      Congestion                           |                                                          2               |      1  2.0|
      Degeneration, Cystic                 | 1                                                                 1      |      4  1.5|
      Eosinophilic Focus                   |       X                                X  X     X              X  X     X|     14     |
      Fibrosis                             |                                                                   2      |      1  2.0|
      Hematopoietic Cell Proliferation     |    1           1                                                         |      2  1.0|
      Hepatodiaphragmatic Nodule           |    X                                                                     |      3     |
      Mixed Cell Focus                     |                                                             X            |      2     |
      Necrosis                             |                                                                   1      |      2  1.0|
      Pigmentation                         |                                     1           1                        |      4  1.0|
      Vacuolization Cytoplasmic            |                                     1                                    |      4  1.5|
      Bile Duct, Hyperplasia               | 1  1  1  1  3  1  1  1     1  3  1  1  2  1  2  1  1  1  1  1  1  1  1  1|     46  1.4|
      Centrilobular, Degeneration          |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Mesentery                               |                         +                                +              +|  11        |
      Cyst                                 |                                                                          |      1  2.0|
      Fat, Necrosis                        |                         2                                2              2|     10  2.2|
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |       2  2  1  1  1  1              1        1     1        1     1      |     18  1.3|
      Cytoplasmic Alteration               |       1                                   1                              |      2  1.0|
      Hyperplasia                          |                                              1                           |      2  2.5|
      Inflammation, Chronic                |                                        3                                 |      1  3.0|
      Artery, Inflammation, Acute          |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  42                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                                                                          |      2  3.0|
      Ulcer                                |                               3                                          |      2  3.0|
      Epithelium, Hyperplasia, Squamous    |                               3                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                                              4     4              1  3   |     15  2.6|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Ulcer                                |                                                                          |      2  2.0|
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   2        |
      Inflammation, Acute                  |                                                                          |      1  2.0|
      Inflammation, Chronic Active         |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       | 2  2  1  2  2  2  3  2  2  2  1  3  1  3  2  1  1  2  1  1  1  2     2  2|     45  1.7|
      Mineralization                       |                                                                   2      |      1  2.0|
      Thrombosis                           | 3           2                                                            |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Adrenal Cortical Nodule    |                                                                          |      1  2.0|
      Hyperplasia                          |                               2                             2            |      8  1.5|
      Hypertrophy                          |                      2                                                   |      1  2.0|
      Vacuolization Cytoplasmic            |                      1                 2  1  1                 3  2      |      9  1.8|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          | 4  1     1  1  2  1           2        3     2              2  2        2|     17  2.2|
      Bilateral, Hyperplasia               |                                                                   3      |      1  3.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       2                                                           2      |      5  2.4|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Cyst                  |                                  1                                       |      2  1.5|
      Pars Distalis, Hemorrhage            |                                                                          |      1  3.0|
      Pars Distalis, Hyperplasia           |          1  3  1        1  1     1     2  4     3  2           1        4|     22  2.3|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ultimobranchial Cyst                 |                                                                          |      1  1.0|
      C-Cell, Hyperplasia                  |       1                       2  1                                       |      7  1.1|
      Follicle, Dilatation                 |       2                                                                  |      1  2.0|
      Follicular Cell, Hyperplasia         |                   1                                                      |      1  1.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  43                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
                                            __________________________________________________________________________|____________|
   Penis                                   |    +                                                                     |   1        |
      Inflammation, Chronic Active         |    3                                                                     |      1  3.0|
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                                          |      1  2.0|
      Hyperplasia                          |          2                 3                                             |      4  2.8|
      Inflammation, Acute                  |                                           4                              |      2  3.0|
      Inflammation, Chronic                |    1  1     2     2           1     2  1     1  1  1              1      |     17  1.3|
      Inflammation, Chronic Active         |          2                                                               |      5  1.6|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Focal                   |                                                                          |      1  2.0|
      Inflammation, Acute                  |                                              3                           |      2  3.5|
      Inflammation, Chronic                |                                                                          |      2  2.0|
      Inflammation, Chronic Active         | 3  2  2           1  2           1  2     2        2     1  1  1  1  1  1|     31  1.7|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Inflammation, Chronic Active         |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
      Atrophy                              |                                                                          |      2  2.5|
      Necrosis                             |                                                                          |      1  4.0|
      Bilateral, Interstitial Cell,        |                                                                          |            |
          Hyperplasia                      |                                                                          |      3  2.3|
      Interstitial Cell, Hyperplasia       | 2     3                 2           2        1              2     1      |      9  2.1|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Depletion Cellular                   |                                     2                                    |      2  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |             +     +           +              +     +  +        +  +  +   |  20        |
      Iliac, Hyperplasia, Lymphoid         |                                                                2         |      1  2.0|
      Iliac, Infiltration Cellular, Plasma |                                                                          |            |
          Cell                             |                                                                          |      1  4.0|
      Mediastinal, Hemorrhage              |                                                                   2      |      1  2.0|
      Renal, Congestion                    |                                              1                           |      1  1.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectasia                              |                2                                            2           2|      4  1.8|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : 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  44                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Ectasia                              |    1                                                                     |      2  2.0|
      Inflammation, Acute                  |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Fibrosis                             | 2  1                          2        2        2     2           2     2|     14  2.3|
      Hematopoietic Cell Proliferation     |                                                             3            |      1  3.0|
      Necrosis                             |                                                       3              3   |      4  3.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                        2                                 |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                                 1                        |      1  1.0|
      Duct, Dilatation                     | 3     4                             1     1  1  3        3  2            |     14  2.4|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Osteodystrophy               |                                                                   3      |      2  3.0|
      Osteopetrosis                        |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hydrocephalus                        |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                                          |      1  2.0|
      Infiltration Cellular, Histiocyte    |          1                                      1              1        1|      6  1.0|
      Inflammation, Chronic                |    1        2  1        1        1                                       |      8  1.1|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |    3  2  2  3     2     3  4  2     1     2           3     3           3|     26  2.2|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Acute                           |                                              2                           |      1  2.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 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  45                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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|      A     |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |    3           3                                                         |      3  2.7|
      Developmental Malformation           |                X     X                                                   |      2     |
      Hydronephrosis                       |                   1                             1                        |      3  1.3|
      Nephropathy                          | 2  2  2  2  2  2  4  2  4  1  2  3  3  3  3  1  3  2  1  1  3  2  4     2|     47  2.3|
      Artery, Inflammation, Acute          |                         3                                                |      1  3.0|
      Artery, Inflammation, Chronic Active |                                                          3               |      1  3.0|
      Renal Tubule, Hyperplasia            |                                                 1                        |      1  1.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                            1           1                                 |      4  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  46                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 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|             
   FISCHER 344 RATS 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|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite Metazoan                    |             X                                      X                     |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Edema                                |                                                                          |             
      Parasite Metazoan                    |                                                                         X|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Edema                                |                                                                          |             
      Hyperplasia, Lymphoid                |                                                                          |             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                              3                           |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |          3        2                    1  1        2                     |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                      X                             X                     |             
      Clear Cell Focus                     |                                                                          |             
      Degeneration, Cystic                 | 4           2        3              2        2  2  1                     |             
      Eosinophilic Focus                   |          X  X     X  X  X           X  X  X  X  X  X        X            |             
      Fibrosis                             |                                                                          |             
      Hematopoietic Cell Proliferation     |                                     1                                    |             
      Hepatodiaphragmatic Nodule           |                                                                          |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |                                                                          |             
      Pigmentation                         |                            1              2  2  1  1                     |             
      Vacuolization Cytoplasmic            |                                              3  3                        |             
      Bile Duct, Hyperplasia               | 3  1  3  2  3        2  1  1  3  2  1  1  1  1     1  1  1  3  2  1  2  1|             
      Centrilobular, Cytomegaly            |                                                 2                        |             
      Centrilobular, Degeneration          |                                                                          |             
      Centrilobular, Necrosis              |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               | +                 +     +  +                       +     +        +      |             
      Inflammation, Acute                  |                                                                          |             
      Fat, Necrosis                        | 2                 3     2  2                       2     2        2      |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              | 2     2  2        1  2     1  3           3        2        1            |             
      Hyperplasia                          |                                                          1           2   |             
      Acinus, Hyperplasia                  |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                              4                           |             
      Ulcer                                | 2                       4  4                 4  4        4        4  3   |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  47                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 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|             
   FISCHER 344 RATS 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|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Epithelium, Hyperplasia, Squamous    |                         3                                            3  1|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              | 1  1           3                 2              2     3  3        4     2|             
      Inflammation, Chronic                |                                                                          |             
      Mineralization                       |                                                                          |             
      Ulcer                                |                            3  3                                3     4   |             
                                            __________________________________________________________________________|             
   Tooth                                   |                               +                                          |             
      Dysplasia                            |                               3                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |    2  1  2  2  1  1  1  2  2     2  2  2  2  1  2  2  2  2  2  3  3  2  1|             
      Thrombosis                           |                            3                                         3  3|             
      Coronary Artery, Inflammation,       |                                                                          |             
          Chronic Active                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                      2        2        2                                 |             
      Vacuolization Cytoplasmic            |                   1                          1                           |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1  1     1  1     4           1     4     4        4  2  1  1  1     2  3|             
      Bilateral, Hyperplasia               |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          4                                                               |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                         4                                                |             
      Pars Distalis, Cyst                  |                                           1           2              2  1|             
      Pars Distalis, Ectasia               |                                                                          |             
      Pars Distalis, Hyperplasia           | 3        3     1  1              3        1              2  4  3  3  2   |             
      Pars Distalis, Thrombosis            |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pigmentation                         |                                                                          |             
      Ultimobranchial Cyst                 |                   1                                                      |             
      C-Cell, Hyperplasia                  |                      1                             3  1     1            |             
      Follicle, Dilatation                 |                      2                                                   |             
      Follicular Cell, Hyperplasia         |                                     2              3     3               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  48                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 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|             
   FISCHER 344 RATS 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|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 3                                               2              2         |             
      Inflammation, Chronic                |    1  1  1  1              1  1  1                    1  2           1  1|             
      Inflammation, Chronic Active         | 2                    1                 1  1  1     2        2  4  1      |             
      Duct, Dilatation                     |             3                                   4                        |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage, Chronic                  |                                           2                              |             
      Hyperplasia, Focal                   |                                                                          |             
      Inflammation, Acute                  |                3                                      4                  |             
      Inflammation, Chronic                |                                           1                              |             
      Inflammation, Chronic Active         |    2  3  2           2  2     1  1  4  2     2  2  2           2  1  1  3|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                                                          |             
      Inflammation, Chronic Active         |             1                                                            |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Interstitial Cell,        |                                                                          |             
          Hyperplasia                      |                      1                                                   |             
      Interstitial Cell, Hyperplasia       |                                  2                                3      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                         2  2                 2  2                        |             
      Hemorrhage                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +        +  +  +           +  +     +              +  +  +  +  +     +|             
      Iliac, Hyperplasia, Lymphoid         |    2                                                                     |             
      Mediastinal, Congestion              |                                  2                                      2|             
      Mediastinal, Hemorrhage              |                                                                2         |             
      Renal, Fibrosis                      |                                                          2               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Ectasia                              |                      1                                                   |             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                         2|             
      Ectasia                              |                   3                    2                                 |             
      Hemorrhage                           |                                                          2               |             
      Necrosis                             |                                     2                                    |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                           3                              |             
      Fibrosis                             |    2     2  2                    2     2     2           2               |             
      Hematopoietic Cell Proliferation     |                                                                          |             
      Necrosis                             |                                                                   3      |             
      Thrombosis                           |                2                                                         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  49                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 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|             
   FISCHER 344 RATS 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|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hemorrhage                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Concretion                           |                                        2                                 |             
      Hyperplasia                          |                                        2                                 |             
      Duct, Dilatation                     | 2  2  1     3        2        3     4        1  1        1        2     2|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Osteodystrophy               |                                                                          |             
      Hyperostosis                         |                                                                2         |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                                                          |             
      Hyperplasia, Lymphoid                |          1                                                               |             
      Infiltration Cellular, Histiocyte    |                               2           1                    1         |             
      Inflammation, Chronic                |    2        2           1     2           1        1     2              1|             
      Alveolar Epithelium, Hyperplasia     |                                                                3  2      |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                  2                                       |             
      Inflammation, Chronic Active         |       1  1     1        3  1  2     1  2  3     3              2         |             
      Squamous Epithelium, Nasolacrimal    |                                                                          |             
          Duct, Hyperplasia                |                                                 3                        |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
      Atrophy                              |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                           3                          2   |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  50                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 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|             
   FISCHER 344 RATS 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|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Hydronephrosis                       |                                                                          |             
      Nephropathy                          | 2  3  2  2  2  1  2  3  3  2  1  2  2  3  3  4  4  3  1  2  2  2  2  1  2|             
      Capsule, Hemorrhage, Chronic         |                                           3                              |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  51                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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| 1|      A     |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
      Parasite Metazoan                    |                X                 X                                       |      4     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
      Edema                                |          4                                                               |      1  4.0|
      Parasite Metazoan                    |                         X                                                |      2     |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Edema                                |          4                                                               |      1  4.0|
      Hyperplasia, Lymphoid                |                                                 2                        |      1  2.0|
      Inflammation, Chronic Active         |                4                                                         |      1  4.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Congestion                           |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Hyperplasia, Lymphoid                |    3  2                 1           2                                    |      9  1.9|
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Angiectasis                          |                   3                                                      |      1  3.0|
      Basophilic Focus                     | X                                   X                          X         |      5     |
      Clear Cell Focus                     |                         X                                                |      1     |
      Degeneration, Cystic                 |       3        3  3        1                             2               |     12  2.3|
      Eosinophilic Focus                   | X     X  X        X     X  X  X                 X        X     X     X   |     23     |
      Fibrosis                             |                                                    2                     |      1  2.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  1.0|
      Hepatodiaphragmatic Nodule           |                   X                                                      |      1     |
      Mixed Cell Focus                     |                               X                                          |      1     |
      Necrosis                             |             1                                                            |      1  1.0|
      Pigmentation                         | 1     1              1        1                          2     1         |     11  1.3|
      Vacuolization Cytoplasmic            |                      2        1     1                          1         |      6  1.8|
      Bile Duct, Hyperplasia               | 1  1  1  1  1  2     1  1  1  1  1  1  3        1  2     3  3  1  1  1  1|     43  1.5|
      Centrilobular, Cytomegaly            |       1                       1                                1         |      4  1.3|
      Centrilobular, Degeneration          |                   2                                   3  2               |      3  2.3|
      Centrilobular, Necrosis              |                   2              1                       2               |      3  1.7|
                                            __________________________________________________________________________|____________|
   Mesentery                               | +        +     +              +        +           +        +            |  14        |
      Inflammation, Acute                  |                                        2                                 |      1  2.0|
      Fat, Necrosis                        | 2        2     3              2                    2        2            |     13  2.2|
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Atrophy                              |             1                 2                 1  2  1                  |     15  1.7|
      Hyperplasia                          | 2                                                  2                     |      4  1.8|
      Acinus, Hyperplasia                  |                               2                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  52                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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| 1|      A     |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                      4                                                   |      1  4.0|
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Acute                  |                                                                          |      1  4.0|
      Ulcer                                |    3                 2                                                   |     10  3.4|
      Epithelium, Hyperplasia, Squamous    |          3           3                 1           3                     |      7  2.4|
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Erosion                              |    4     2     4     2                    4           2  4              2|     17  2.6|
      Inflammation, Chronic                |                                        2                                 |      1  2.0|
      Mineralization                       |                               2                    2                     |      2  2.0|
      Ulcer                                |                                                             3            |      5  3.2|
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   1        |
      Dysplasia                            |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       | 2  2     1  1        2  1  2  1  1  2  3  2  2  2  2  2  1  1  1     2   |     43  1.7|
      Thrombosis                           |                                  3                       2  3            |      6  2.8|
      Coronary Artery, Inflammation,       |                                                                          |            |
          Chronic Active                   |       4                                                                  |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |       1     1              2                    3                        |      7  1.9|
      Vacuolization Cytoplasmic            |       1                                            4                    1|      5  1.6|
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          | 2           3                          4  1     2  4        4            |     22  2.3|
      Bilateral, Hyperplasia               |                         4                                                |      1  4.0|
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |                               2                                          |      2  3.0|
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                    2                     |      1  2.0|
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Angiectasis           |                                     3                                    |      2  3.5|
      Pars Distalis, Cyst                  |             2           1        1              1                        |      8  1.4|
      Pars Distalis, Ectasia               |                   3                                                      |      1  3.0|
      Pars Distalis, Hyperplasia           | 1                 4  4                          4  4                     |     16  2.7|
      Pars Distalis, Thrombosis            |                                        4                                 |      1  4.0|
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : 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: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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| 1|      A     |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Pigmentation                         |                                     1                                    |      1  1.0|
      Ultimobranchial Cyst                 |                                                                          |      1  1.0|
      C-Cell, Hyperplasia                  |                                                                1         |      5  1.4|
      Follicle, Dilatation                 |                                                                          |      1  2.0|
      Follicular Cell, Hyperplasia         |                               1                 1                        |      5  2.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +|  47        |
      Hyperplasia                          |                                                                          |      3  2.3|
      Inflammation, Chronic                |          1  1  1  1  1        2     1     1  1  1  1  1     1  1         |     25  1.1|
      Inflammation, Chronic Active         | 2  2  4                                                           2     1|     14  1.9|
      Duct, Dilatation                     |                                                                          |      2  3.5|
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
      Hemorrhage, Chronic                  |                                                                          |      1  2.0|
      Hyperplasia, Focal                   |                                     1                                    |      1  1.0|
      Inflammation, Acute                  |                                                                          |      2  3.5|
      Inflammation, Chronic                |                                                                          |      1  1.0|
      Inflammation, Chronic Active         | 1  2              1  3  1  2  2        3  4     2  1        4  1         |     29  2.0|
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Inflammation, Acute                  |                                                             1            |      1  1.0|
      Inflammation, Chronic Active         |                                                                          |      1  1.0|
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
      Bilateral, Interstitial Cell,        |                                                                          |            |
          Hyperplasia                      |                                                    4                     |      2  2.5|
      Interstitial Cell, Hyperplasia       |                            1     3                          1     2      |      6  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Depletion Cellular                   |                                                                          |      4  2.0|
      Hemorrhage                           |             2                                                            |      1  2.0|
                                            __________________________________________________________________________|____________|
   Lymph Node                              |    +     +     +     +  +              +  +        +        +     +     +|  25        |
      Iliac, Hyperplasia, Lymphoid         |                                                                          |      1  2.0|
      Mediastinal, Congestion              |                      2  2              2                                 |      5  2.0|
      Mediastinal, Hemorrhage              |                                                                          |      1  2.0|
      Renal, Fibrosis                      |                                                                          |      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  54                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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| 1|      A     |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion                           |                   2                                                      |      1  2.0|
      Ectasia                              |                   2        2                                             |      3  1.7|
      Inflammation, Chronic Active         |                      4                                                   |      1  4.0|
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Congestion                           |                   4                                                      |      2  3.0|
      Ectasia                              |                         3                                                |      3  2.7|
      Hemorrhage                           |                                                                          |      1  2.0|
      Necrosis                             |          3     3                                                         |      3  2.7|
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Congestion                           |                                                                          |      1  3.0|
      Fibrosis                             |       2                                   1        3        3            |     11  2.1|
      Hematopoietic Cell Proliferation     |                                                       3                  |      1  3.0|
      Necrosis                             |          2                                                               |      2  2.5|
      Thrombosis                           |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Fibrosis                             | 2                                                                        |      1  2.0|
      Hemorrhage                           |                                           3                              |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Concretion                           |                                                                          |      1  2.0|
      Hyperplasia                          |                               1                 1                        |      3  1.3|
      Duct, Dilatation                     |                      1     3                       4        3            |     16  2.2|
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                               4                                          |      1  4.0|
      Inflammation, Acute                  |             2                                                            |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Osteodystrophy               |                                                    3                     |      1  3.0|
      Hyperostosis                         |                                                                          |      1  2.0|
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                       +                  |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  55                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|      T (*) |
 _____________________________________________________________________________________________________________________|            |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   FISCHER 344 RATS 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|      T     |
                               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| 1|      A     |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Congestion                           |                                              3                           |      1  3.0|
      Hyperplasia, Lymphoid                |                                                                          |      1  1.0|
      Infiltration Cellular, Histiocyte    |             1                                                            |      4  1.3|
      Inflammation, Chronic                |                      1                                1                  |     10  1.4|
      Alveolar Epithelium, Hyperplasia     |                      2                                                   |      3  2.3|
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  2.0|
      Inflammation, Chronic Active         | 3  3              4        3           2                       1  1      |     18  2.1|
      Squamous Epithelium, Nasolacrimal    |                                                                          |            |
          Duct, Hyperplasia                |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                               +                                          |   1        |
      Atrophy                              |                               4                                          |      1  4.0|
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                      +                                                   |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Cyst                                 |                                                 3                        |      3  2.7|
      Hydronephrosis                       |                                                    1                     |      1  1.0|
      Nephropathy                          | 2  1  3  3  2  1  1  2  3  3  4     3  1  3     3  4  1  2  2  3  2  1   |     47  2.3|
      Capsule, Hemorrhage, Chronic         |                                                                          |      1  3.0|
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Hemorrhage                           |    2                                                                     |      1  2.0|
 __________________________________________________________________________________________________________________________________ 

  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        

                                                             Page  56                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                  2                                       |             
      Inflammation, Acute                  |                         3                                                |             
      Inflammation, Chronic                |                                                                          |             
      Parasite Metazoan                    |                            X                                   X         |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                                                          |             
      Parasite Metazoan                    |    X                                                                     |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectopic Pancreas                     |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |             2     3                                                      |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                              2                           |             
      Clear Cell Focus                     |                   X              X                             X         |             
      Degeneration, Cystic                 |       1     1                    2        1  1        2              1  4|             
      Developmental Malformation           |                            X                                             |             
      Eosinophilic Focus                   | X     X  X  X  X           X  X           X                 X  X     X  X|             
      Fibrosis                             |                                              1                           |             
      Mixed Cell Focus                     |                                                                X     X   |             
      Necrosis                             |                                                                          |             
      Pigmentation                         |    1  1                    3  2        2  1  2        1     1  2  1  1   |             
      Thrombosis                           |                                                    2                     |             
      Vacuolization Cytoplasmic            | 1                 1                    2              1        1  2      |             
      Bile Duct, Hyperplasia               | 1  1  1  1  1  3  1  3  2  3  3  1  3  3  1  1     3  1  3  1  1     1  2|             
      Centrilobular, Cytomegaly            |    1  1                                                        1         |             
      Centrilobular, Degeneration          |    1                                         3                           |             
      Periportal, Fibrosis                 |    1                                                                     |             
                                            __________________________________________________________________________|             
   Mesentery                               | +                 +              +           +                           |             
      Hemorrhage                           |                                              3                           |             
      Fat, Necrosis                        | 1                 2              2                                       |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                                                          |             
      Pharyngeal, Hyperplasia              |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              | 1  1  1                    2     1  1        1     1     1               |             
      Hyperplasia                          |                   2                                                  3   |             
      Inflammation, Chronic                |             1                                                           4|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
      Epithelium, Hyperplasia, Squamous    |    4                                         4                           |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  57                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |          4              3     4                          2               |             
      Inflammation, Chronic Active         |                                                                          |             
      Mineralization                       |                                        2     1                           |             
      Ulcer                                |                                                    2                     |             
                                            __________________________________________________________________________|             
   Tooth                                   |       +                                                                  |             
      Inflammation, Chronic Active         |       3                                                                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1  1  2  2  1  2  2     1  3  2  2  1        2  1  2  2  1  2  2  2  2  2|             
      Mineralization                       |                                        3     2                           |             
      Thrombosis                           |                               2                    3                     |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                              3                           |             
      Hyperplasia                          |       1     4           1              1                       2     2   |             
      Vacuolization Cytoplasmic            |          3                                                     3         |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    2        1  2  1     1     4        4           1  2  1           2   |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                              3        2                  |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Cyst                  |                                                                          |             
      Pars Distalis, Hyperplasia           |    4     4        1  1     2  1  1                       2               |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                      1                                               1   |             
      Follicle, Dilatation                 |                                                                          |             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Inflammation, Chronic                |                                              1     2                     |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    2        2                                                        3   |             
      Inflammation, Chronic                |                2     1  2  1                 1           1     1         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  58                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Inflammation, Chronic Active         | 2        4                    1           1           2              3  3|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
      Inflammation, Chronic                | 1           1                    1                                   1   |             
      Inflammation, Chronic Active         |       3           2  2     1  2        1  3  1  1  1  2     2     2      |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Dilatation                           |                   3                                                      |             
      Inflammation, Acute                  |                                     1                                    |             
      Inflammation, Chronic Active         |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Thrombosis                           |                   4                                                      |             
      Bilateral, Interstitial Cell,        |                                                                          |             
          Hyperplasia                      |       2                                                           3      |             
      Interstitial Cell, Hyperplasia       |          2                          3                                    |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Depletion Cellular                   |                                                 2                        |             
      Fibrosis                             |                         3                                                |             
                                            __________________________________________________________________________|             
   Lymph Node                              |          +           +  +     +     +  +           +     +        +     +|             
      Mediastinal, Ectasia                 |                                                                         2|             
      Mediastinal, Hemorrhage              |                                        2                                 |             
      Mediastinal, Pigmentation            |                                                                         2|             
      Pancreatic, Congestion               |                                        2                                 |             
      Pancreatic, Hyperplasia, Lymphoid    |                                                                          |             
      Pancreatic, Necrosis                 |                         3                                                |             
      Pancreatic, Pigmentation             |                                                                          |             
      Renal, Congestion                    |                                                                          |             
      Renal, Edema                         |                                                    4                     |             
      Renal, Hyperplasia, Lymphoid         |                                                                   1      |             
      Renal, Pigmentation                  |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                           2                              |             
      Ectasia                              |                                                                2         |             
      Hyperplasia, Lymphoid                |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              | 2                                                                        |             
      Fibrosis                             |                   1                                                      |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                              3                           |             
      Fibrosis                             |                               1                                         2|             
      Hyperplasia, Focal                   |                                        2                                 |             
      Necrosis                             |          2                                                               |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  59                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                                             3            |             
      Hyperplasia                          |       1                    1                                             |             
      Duct, Dilatation                     |       3                       2                 1     2           3  3   |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                                     X              X                     |             
      Hyperkeratosis                       |                                                                         4|             
      Hyperplasia, Squamous                |                                                                         2|             
      Necrosis                             |                                                                          |             
      Subcutaneous Tissue, Inflammation,   |                                                                          |             
           Chronic Active                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Osteodystrophy               |    3                                   3     2                           |             
      Osteopetrosis                        |                            3                                             |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                           3                              |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Infiltration Cellular, Histiocyte    | 1     1                                1        1                        |             
      Inflammation, Chronic                |                1  2  2  1     1                    1                    1|             
                                            __________________________________________________________________________|             
   Nose                                    | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                2                                                         |             
      Inflammation, Chronic                |                                                                          |             
      Inflammation, Chronic Active         |             1     2     2  3  3  1           3     1  1  3  2  3     3   |             
      Nasolacrimal Duct, Cyst              |    2                                                                     |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Cyst                                 |    3                                   3     4                 2  3      |             
      Nephropathy                          | 2  4  3  2  2  2  3  2  3  2  3  2  1  4  2  4  1  3  3  3  2  3  3  2  3|             
      Renal Tubule, Hyperplasia            |    2                                                  2                  |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  60                                                               
NTP Experiment-Test: 55301-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 10:52:14  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
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