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TDMS Study 55301-05 Pathology Tables

 
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97
Route: DOSED WATER                                                                                                Time: 11:05:00




       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




































a  Number of animals examined microscopically at site and number of animals with lesion

                                                              Page   1


NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                     15            5           14           22                                     
    Moribund Sacrifice                                 3            8            7            2                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                32           37           29           26                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (50)         (50)         (50)                                   
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Parasite Metazoan                                3 (6%)       3 (6%)       3 (6%)       1 (2%)                                
   Intestine Large, Rectum                            (50)         (50)         (50)         (50)                                   
      Parasite Metazoan                                1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
   Intestine Large, Cecum                             (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Chronic Active                                               1 (2%)                                             
      Parasite Metazoan                                                          1 (2%)                                             
      Ulcer                                                         1 (2%)                                                          
   Intestine Small, Duodenum                          (50)         (50)         (50)         (50)                                   
      Ectopic Pancreas                                 1 (2%)                                                                       
      Inflammation, Chronic Active                                               1 (2%)                                             
   Intestine Small, Ileum                             (50)         (49)         (50)         (50)                                   
      Hyperplasia, Lymphoid                            3 (6%)       2 (4%)       2 (4%)       5 (10%)                               
      Inflammation, Chronic Active                                                            1 (2%)                                
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)       2 (4%)       3 (6%)       2 (4%)                                
      Basophilic Focus                                38 (76%)     28 (56%)     11 (22%)                                            
      Clear Cell Focus                                 4 (8%)       9 (18%)     11 (22%)     16 (32%)                               
      Congestion                                       4 (8%)       1 (2%)       3 (6%)       2 (4%)                                
      Developmental Malformation                       1 (2%)       2 (4%)       1 (2%)                                             
      Eosinophilic Focus                              19 (38%)     24 (48%)     22 (44%)     15 (30%)                               
      Fibrosis                                         1 (2%)       1 (2%)                                                          
      Hematopoietic Cell Proliferation                              1 (2%)       1 (2%)       2 (4%)                                
      Hemorrhage                                                    1 (2%)       1 (2%)                                             
      Hepatodiaphragmatic Nodule                       9 (18%)      8 (16%)      3 (6%)       3 (6%)                                
      Inflammation, Chronic Active                     9 (18%)      1 (2%)       2 (4%)       4 (8%)                                
      Mitotic Alteration                               1 (2%)                                 1 (2%)                                
      Mixed Cell Focus                                 2 (4%)       4 (8%)       1 (2%)       5 (10%)                               
      Necrosis                                         6 (12%)      1 (2%)       1 (2%)                                             
      Pigmentation                                     6 (12%)      2 (4%)       6 (12%)     17 (34%)                               
      Tension Lipidosis                                3 (6%)       1 (2%)                                                          
      Vacuolization Cytoplasmic                       10 (20%)      7 (14%)      9 (18%)     18 (36%)                               

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    2                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Bile Duct, Hyperplasia                          20 (40%)     29 (58%)     34 (68%)     29 (58%)                               
      Capsule, Inflammation, Chronic                                                          2 (4%)                                
      Centrilobular, Cytomegaly                                     1 (2%)       4 (8%)      20 (40%)                               
      Centrilobular, Degeneration                      1 (2%)       2 (4%)       2 (4%)       7 (14%)                               
      Centrilobular, Necrosis                          1 (2%)       2 (4%)       1 (2%)                                             
   Mesentery                                          (9)          (11)         (7)          (12)                                   
      Ectopic Spleen                                                             1 (14%)                                            
      Inflammation                                                                            1 (8%)                                
      Fat, Necrosis                                    8 (89%)      9 (82%)      6 (86%)     11 (92%)                               
   Oral Mucosa                                        (2)          (1)                       (2)                                    
      Pharyngeal, Hyperplasia                                                                 1 (50%)                               
      Pharyngeal, Inflammation, Acute                               1 (100%)                                                        
   Pancreas                                           (49)         (50)         (50)         (50)                                   
      Atrophy                                         22 (45%)     14 (28%)     13 (26%)     14 (28%)                               
      Cytoplasmic Alteration                           1 (2%)                                                                       
      Ectopic Liver                                                 2 (4%)       2 (4%)       3 (6%)                                
      Hyperplasia                                                   3 (6%)       2 (4%)                                             
      Inflammation, Chronic                                                      1 (2%)       2 (4%)                                
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                                       2 (4%)       3 (6%)       1 (2%)                                
      Cytoplasmic Alteration                                        1 (2%)                    1 (2%)                                
      Inflammation, Chronic                                         2 (4%)                                                          
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Fibrosis                                                                   1 (2%)                                             
      Hyperkeratosis                                   1 (2%)                                                                       
      Inflammation, Acute                              1 (2%)                    1 (2%)                                             
      Inflammation, Chronic                                                      1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     2 (4%)       1 (2%)       2 (4%)       1 (2%)                                
      Ulcer                                            3 (6%)       3 (6%)       4 (8%)       4 (8%)                                
      Epithelium, Hyperplasia, Squamous                2 (4%)       2 (4%)       2 (4%)       1 (2%)                                
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
      Erosion                                          6 (12%)      9 (18%)      9 (18%)      7 (14%)                               
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Mineralization                                                             2 (4%)                                             
      Ulcer                                            1 (2%)       1 (2%)       3 (6%)                                             
   Tongue                                                                       (1)          (2)                                    
      Epithelium, Hyperplasia                                                    1 (100%)     1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (49)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  42 (86%)     43 (86%)     43 (86%)     36 (72%)                               
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Mineralization                                   1 (2%)                                                                       
      Thrombosis                                                                 2 (4%)       1 (2%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    3                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                1 (2%)                                                                       
      Atrophy                                                                    1 (2%)                                             
      Congestion                                                    1 (2%)                    1 (2%)                                
      Cyst                                                          1 (2%)                    1 (2%)                                
      Hematopoietic Cell Proliferation                 1 (2%)                                                                       
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia                                     11 (22%)     12 (24%)      9 (18%)      6 (12%)                               
      Vacuolization Cytoplasmic                        6 (12%)      8 (16%)      6 (12%)      3 (6%)                                
   Adrenal Medulla                                    (50)         (50)         (50)         (49)                                   
      Hyperplasia                                      5 (10%)      7 (14%)      8 (16%)      2 (4%)                                
      Necrosis                                                      1 (2%)                                                          
   Islets, Pancreatic                                 (49)         (50)         (50)         (50)                                   
      Hyperplasia                                                                1 (2%)       1 (2%)                                
   Parathyroid Gland                                  (48)         (50)         (48)         (50)                                   
      Hyperplasia                                      1 (2%)                                                                       
   Pituitary Gland                                    (49)         (50)         (50)         (50)                                   
      Pigmentation                                                               1 (2%)                                             
      Pars Distalis, Angiectasis                      11 (22%)      9 (18%)     12 (24%)      4 (8%)                                
      Pars Distalis, Cyst                             16 (33%)     18 (36%)     20 (40%)      8 (16%)                               
      Pars Distalis, Ectasia                                        1 (2%)                                                          
      Pars Distalis, Hemorrhage                        1 (2%)                                                                       
      Pars Distalis, Hyperplasia                      22 (45%)     29 (58%)     21 (42%)     18 (36%)                               
      Pars Intermedia, Hyperplasia                     1 (2%)                                                                       
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Ultimobranchial Cyst                                          3 (6%)                    1 (2%)                                
      C-Cell, Hyperplasia                             16 (32%)     17 (34%)     13 (26%)     10 (20%)                               
      Follicular Cell, Hyperplasia                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (47)         (48)         (50)         (49)                                   
      Hyperplasia                                      1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
      Inflammation, Acute                              1 (2%)       2 (4%)                                                          
      Inflammation, Chronic                            3 (6%)       1 (2%)       5 (10%)      2 (4%)                                
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       2 (4%)       1 (2%)                                
      Vacuolization Cytoplasmic                                                               1 (2%)                                
      Bilateral, Inflammation, Acute                                             1 (2%)                                             
      Duct, Ectasia                                    3 (6%)       5 (10%)      4 (8%)       2 (4%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    4                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
   Ovary                                              (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)                                                                       
      Cyst                                             3 (6%)       7 (14%)      4 (8%)       2 (4%)                                
      Hyperplasia                                                   1 (2%)                                                          
      Inflammation, Chronic                            1 (2%)                                 1 (2%)                                
      Pigmentation                                                               1 (2%)                                             
      Bilateral, Cyst                                               1 (2%)                    2 (4%)                                
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)                                                          
      Cyst                                                          1 (2%)                    1 (2%)                                
      Developmental Malformation                                                 1 (2%)                                             
      Dilatation                                                    1 (2%)       1 (2%)       2 (4%)                                
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Hyperplasia                                                                             1 (2%)                                
      Hyperplasia, Cystic                              6 (12%)                   5 (10%)      7 (14%)                               
      Inflammation, Acute                                                                     1 (2%)                                
      Inflammation, Chronic                                         1 (2%)                    1 (2%)                                
      Inflammation, Chronic Active                                  1 (2%)                                                          
      Metaplasia, Squamous                                                       1 (2%)                                             
      Necrosis                                         1 (2%)                                 1 (2%)                                
      Cervix, Hypertrophy                                                        1 (2%)                                             
      Cervix, Inflammation, Chronic                                                           1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Depletion Cellular                               1 (2%)                    2 (4%)       2 (4%)                                
      Fibrosis                                         1 (2%)       1 (2%)                                                          
      Hyperplasia                                      3 (6%)       4 (8%)                    1 (2%)                                
      Hyperplasia, Reticulum Cell                                   1 (2%)                                                          
      Necrosis                                                                   1 (2%)                                             
      Erythroid Cell, Hyperplasia                                                1 (2%)                                             
      Myeloid Cell, Hyperplasia                                     1 (2%)                                                          
   Lymph Node                                         (7)          (9)          (15)         (19)                                   
      Iliac, Congestion                                2 (29%)                                                                      
      Iliac, Ectasia                                                                          2 (11%)                               
      Mediastinal, Congestion                          3 (43%)      1 (11%)      4 (27%)      1 (5%)                                
      Mediastinal, Hyperplasia, Lymphoid                                         1 (7%)                                             
      Mediastinal, Pigmentation                        1 (14%)                                1 (5%)                                
      Pancreatic, Congestion                                                     1 (7%)                                             
      Pancreatic, Pigmentation                                      1 (11%)                                                         
      Renal, Congestion                                1 (14%)      1 (11%)      1 (7%)                                             
      Renal, Ectasia                                                1 (11%)                   1 (5%)                                
      Renal, Hyperplasia, Lymphoid                                                            1 (5%)                                
   Lymph Node, Mandibular                             (49)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                                                       

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    5                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Congestion                                                    1 (2%)       1 (2%)                                             
      Ectasia                                          3 (6%)       4 (8%)       9 (18%)      2 (4%)                                
      Edema                                                                                   1 (2%)                                
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                    1 (2%)                                
      Hyperplasia, Plasma Cell                         1 (2%)                                                                       
      Infiltration Cellular, Plasma Cell                            1 (2%)                                                          
      Necrosis                                                                   1 (2%)                                             
   Lymph Node, Mesenteric                             (49)         (50)         (50)         (50)                                   
      Congestion                                       2 (4%)                    3 (6%)                                             
      Ectasia                                                                    4 (8%)                                             
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia, Lymphoid                                         2 (4%)                    2 (4%)                                
      Inflammation, Acute                                                                     1 (2%)                                
      Inflammation, Chronic                                                                   1 (2%)                                
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                                                                 1 (2%)                                
      Congestion                                       1 (2%)                    2 (4%)                                             
      Fibrosis                                         2 (4%)       3 (6%)       3 (6%)       4 (8%)                                
      Hematopoietic Cell Proliferation                 2 (4%)       4 (8%)                    2 (4%)                                
      Hemorrhage                                                    2 (4%)                                                          
      Metaplasia, Osseous                                           1 (2%)                                                          
      Necrosis                                                      1 (2%)       2 (4%)       1 (2%)                                
      Pigmentation                                                                            1 (2%)                                
      Capsule, Inflammation, Chronic                                                          1 (2%)                                
   Thymus                                             (50)         (50)         (50)         (50)                                   
      Congestion                                                                 1 (2%)                                             
      Cyst                                                                       1 (2%)                                             
      Ectopic Parathyroid Gland                        2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Fibrosis                                                      1 (2%)                                                          
      Inflammation, Acute                              1 (2%)                                                                       
      Inflammation, Chronic                                                                   1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Galactocele                                      3 (6%)       5 (10%)      1 (2%)                                             
      Hyperplasia                                      5 (10%)      2 (4%)       6 (12%)      5 (10%)                               
      Inflammation, Chronic Active                                               1 (2%)                                             
      Duct, Dilatation                                13 (26%)      9 (18%)     13 (26%)     13 (26%)                               
   Skin                                               (50)         (50)         (50)         (50)                                   
      Hyperkeratosis                                                             2 (4%)                                             
      Hyperplasia, Squamous                            2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Acute                              1 (2%)                                 1 (2%)                                
      Inflammation, Chronic                            1 (2%)                                                                       
      Inflammation, Chronic Active                     2 (4%)       1 (2%)                    1 (2%)                                
      Subcutaneous Tissue, Fibrosis                                 1 (2%)                                                          

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    6                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Osteopetrosis                                    9 (18%)     12 (24%)     10 (20%)      5 (10%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)       1 (2%)                    2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)                                                                       
      Hemorrhage                                                                              1 (2%)                                
      Infiltration Cellular, Histiocyte               13 (26%)     10 (20%)      9 (18%)     11 (22%)                               
      Inflammation, Chronic                            9 (18%)      8 (16%)      6 (12%)      8 (16%)                               
      Bronchiole, Alveolus, Hyperplasia                                          1 (2%)                                             
   Nose                                               (50)         (50)         (50)         (50)                                   
      Congestion                                                                 1 (2%)                                             
      Cyst                                             1 (2%)       1 (2%)                                                          
      Hemorrhage                                                                              1 (2%)                                
      Inflammation, Chronic                            2 (4%)                    3 (6%)                                             
      Inflammation, Chronic Active                    15 (30%)     15 (30%)     16 (32%)     19 (38%)                               
      Nasolacrimal Duct, Cyst                                       2 (4%)                                                          
      Nasolacrimal Duct, Inflammation, Chronic                                                                                      
          Active                                       1 (2%)                    1 (2%)                                             
      Respiratory Epithelium, Hyperplasia                                                     1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                                          (1)          (2)                                    
      Hemorrhage                                                                 1 (100%)     2 (100%)                              
   Harderian Gland                                    (1)                                                                           
      Inflammation, Chronic                            1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Accumulation, Hyaline Droplet                                                           1 (2%)                                
      Congestion                                       2 (4%)                    1 (2%)                                             
      Cyst                                                                       1 (2%)                                             
      Hydronephrosis                                                2 (4%)                                                          

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    7                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Inflammation, Acute                                                                     1 (2%)                                
      Mineralization                                   3 (6%)                    4 (8%)       6 (12%)                               
      Nephropathy                                     41 (82%)     42 (84%)     35 (70%)     37 (74%)                               
      Pigmentation                                                               2 (4%)       1 (2%)                                
      Renal Tubule, Hyperplasia                                                               1 (2%)                                
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Inflammation, Chronic                                         3 (6%)       1 (2%)       2 (4%)                                
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    8                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                11           13           15           10                                     
    Natural Death                                     14           17           10           24                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                25           20           25           16                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (48)         (50)         (49)                                   
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Inflammation, Acute                                                        1 (2%)                                             
      Inflammation, Chronic                                                      1 (2%)                                             
      Parasite Metazoan                                4 (8%)       4 (8%)       3 (6%)       2 (4%)                                
   Intestine Large, Rectum                            (50)         (48)         (50)         (49)                                   
      Edema                                                         1 (2%)                                                          
      Parasite Metazoan                                4 (8%)       2 (4%)                    1 (2%)                                
   Intestine Large, Cecum                             (49)         (47)         (50)         (49)                                   
      Edema                                                         1 (2%)                                                          
      Hyperplasia, Lymphoid                                         1 (2%)                                                          
      Inflammation, Acute                              1 (2%)                    1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                                  1 (2%)                                                          
      Parasite Metazoan                                                          1 (2%)       1 (2%)                                
      Ulcer                                            1 (2%)                                                                       
   Intestine Small, Duodenum                          (50)         (47)         (50)         (48)                                   
      Ectopic Pancreas                                                           1 (2%)                                             
   Intestine Small, Jejunum                           (50)         (47)         (50)         (47)                                   
      Congestion                                                    1 (2%)                                                          
   Intestine Small, Ileum                             (50)         (47)         (50)         (47)                                   
      Fibrosis                                         1 (2%)                                                                       
      Hyperplasia, Lymphoid                            6 (12%)      9 (19%)      3 (6%)       4 (9%)                                
   Liver                                              (50)         (49)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)       1 (2%)       1 (2%)                                
      Basophilic Focus                                12 (24%)      5 (10%)                   1 (2%)                                
      Clear Cell Focus                                 7 (14%)      1 (2%)       7 (14%)      4 (8%)                                
      Congestion                                       1 (2%)                                                                       
      Degeneration, Cystic                             4 (8%)      12 (24%)     11 (22%)      3 (6%)                                
      Developmental Malformation                                                 1 (2%)       1 (2%)                                
      Eosinophilic Focus                              14 (28%)     23 (47%)     23 (46%)     13 (26%)                               
      Fibrosis                                         1 (2%)       1 (2%)       1 (2%)      10 (20%)                               
      Hematopoietic Cell Proliferation                 2 (4%)       1 (2%)                                                          
      Hepatodiaphragmatic Nodule                       3 (6%)       1 (2%)                                                          
      Mitotic Alteration                                                                      2 (4%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page    9                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Mixed Cell Focus                                 2 (4%)       1 (2%)       3 (6%)       1 (2%)                                
      Necrosis                                         2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Pigmentation                                     4 (8%)      11 (22%)     20 (40%)     25 (50%)                               
      Thrombosis                                                                 1 (2%)                                             
      Vacuolization Cytoplasmic                        4 (8%)       6 (12%)     13 (26%)     17 (34%)                               
      Bile Duct, Hyperplasia                          46 (92%)     43 (88%)     44 (88%)     49 (98%)                               
      Centrilobular, Cytomegaly                                     4 (8%)       8 (16%)      6 (12%)                               
      Centrilobular, Degeneration                      1 (2%)       3 (6%)       2 (4%)       8 (16%)                               
      Centrilobular, Necrosis                                       3 (6%)                    5 (10%)                               
      Periportal, Fibrosis                                                       2 (4%)      29 (58%)                               
   Mesentery                                          (11)         (14)         (7)          (8)                                    
      Cyst                                             1 (9%)                                                                       
      Hemorrhage                                                                 1 (14%)                                            
      Inflammation, Acute                                           1 (7%)                                                          
      Fat, Necrosis                                   10 (91%)     13 (93%)      6 (86%)      8 (100%)                              
   Oral Mucosa                                        (1)                       (2)                                                 
      Pharyngeal, Hyperplasia                                                    1 (50%)                                            
   Pancreas                                           (50)         (48)         (50)         (49)                                   
      Atrophy                                         18 (36%)     15 (31%)     17 (34%)     12 (24%)                               
      Cytoplasmic Alteration                           2 (4%)                                                                       
      Hyperplasia                                      2 (4%)       4 (8%)       2 (4%)       3 (6%)                                
      Inflammation, Chronic                            1 (2%)                    3 (6%)                                             
      Acinus, Hyperplasia                                           1 (2%)                                                          
      Artery, Inflammation, Acute                      1 (2%)                                                                       
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Cellular Alteration                                                                     1 (2%)                                
      Inflammation, Chronic Active                                  1 (2%)                                                          
   Stomach, Forestomach                               (50)         (49)         (50)         (49)                                   
      Hyperkeratosis                                                                          2 (4%)                                
      Inflammation, Acute                                           1 (2%)                    1 (2%)                                
      Inflammation, Chronic Active                     2 (4%)                                 8 (16%)                               
      Ulcer                                            2 (4%)      10 (20%)      3 (6%)       4 (8%)                                
      Epithelium, Hyperplasia, Squamous                1 (2%)       7 (14%)      7 (14%)     11 (22%)                               
   Stomach, Glandular                                 (50)         (49)         (50)         (49)                                   
      Erosion                                         15 (30%)     17 (35%)     12 (24%)     12 (24%)                               
      Inflammation, Acute                                                                     1 (2%)                                
      Inflammation, Chronic                            1 (2%)       1 (2%)                                                          
      Inflammation, Chronic Active                                               1 (2%)       1 (2%)                                
      Mineralization                                                2 (4%)       2 (4%)       8 (16%)                               
      Necrosis                                                                                1 (2%)                                
      Ulcer                                            2 (4%)       5 (10%)      1 (2%)       1 (2%)                                
   Tooth                                              (2)          (1)          (1)                                                 
      Dysplasia                                                     1 (100%)                                                        
      Inflammation, Acute                              1 (50%)                                                                      
      Inflammation, Chronic Active                     1 (50%)                   1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   10                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  45 (90%)     43 (86%)     43 (86%)     46 (92%)                               
      Mineralization                                   1 (2%)                    3 (6%)       2 (4%)                                
      Thrombosis                                       2 (4%)       6 (12%)      3 (6%)       4 (8%)                                
      Coronary Artery, Inflammation, Chronic Active                 1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                1 (2%)                                 1 (2%)                                
      Congestion                                                                 1 (2%)                                             
      Hyperplasia                                      8 (16%)      7 (14%)      7 (14%)      2 (4%)                                
      Hypertrophy                                      1 (2%)                                 2 (4%)                                
      Vacuolization Cytoplasmic                        9 (18%)      5 (10%)      9 (18%)      7 (14%)                               
   Adrenal Medulla                                    (50)         (49)         (50)         (49)                                   
      Hyperplasia                                     17 (34%)     22 (45%)     19 (38%)     15 (31%)                               
      Bilateral, Hyperplasia                           1 (2%)       1 (2%)                    1 (2%)                                
   Islets, Pancreatic                                 (50)         (48)         (50)         (49)                                   
      Hyperplasia                                      5 (10%)      2 (4%)       1 (2%)       1 (2%)                                
   Parathyroid Gland                                  (50)         (50)         (50)         (48)                                   
      Hyperplasia                                                   1 (2%)       3 (6%)       3 (6%)                                
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Pars Distalis, Angiectasis                                    2 (4%)       2 (4%)       2 (4%)                                
      Pars Distalis, Cyst                              2 (4%)       8 (16%)      3 (6%)       1 (2%)                                
      Pars Distalis, Degeneration                                                             1 (2%)                                
      Pars Distalis, Ectasia                                        1 (2%)                                                          
      Pars Distalis, Hemorrhage                        1 (2%)                                                                       
      Pars Distalis, Hyperplasia                      22 (44%)     16 (32%)     18 (36%)     12 (24%)                               
      Pars Distalis, Thrombosis                                     1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (50)         (49)                                   
      Pigmentation                                                  1 (2%)                                                          
      Ultimobranchial Cyst                             1 (2%)       1 (2%)                    1 (2%)                                
      C-Cell, Hyperplasia                              7 (14%)      5 (10%)      3 (6%)       3 (6%)                                
      Follicle, Dilatation                             1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Follicular Cell, Hyperplasia                     1 (2%)       5 (10%)      1 (2%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   11                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (49)         (49)         (49)         (48)                                   
      Fibrosis                                                                   1 (2%)                                             
      Inflammation, Chronic                                                      2 (4%)                                             
   Penis                                              (1)                                                                           
      Inflammation, Chronic Active                     1 (100%)                                                                     
   Preputial Gland                                    (50)         (47)         (49)         (48)                                   
      Atrophy                                          1 (2%)                                                                       
      Hyperplasia                                      4 (8%)       3 (6%)       5 (10%)      4 (8%)                                
      Inflammation, Acute                              2 (4%)                                 2 (4%)                                
      Inflammation, Chronic                           17 (34%)     25 (53%)     17 (35%)     23 (48%)                               
      Inflammation, Chronic Active                     5 (10%)     14 (30%)     14 (29%)      5 (10%)                               
      Duct, Dilatation                                              2 (4%)                    2 (4%)                                
   Prostate                                           (50)         (48)         (50)         (49)                                   
      Hemorrhage, Chronic                                           1 (2%)                                                          
      Hyperplasia, Focal                               1 (2%)       1 (2%)       4 (8%)       2 (4%)                                
      Inflammation, Acute                              2 (4%)       2 (4%)                    1 (2%)                                
      Inflammation, Chronic                            2 (4%)       1 (2%)       4 (8%)       3 (6%)                                
      Inflammation, Chronic Active                    31 (62%)     29 (60%)     24 (48%)     22 (45%)                               
   Seminal Vesicle                                    (50)         (47)         (50)         (48)                                   
      Dilatation                                                                 1 (2%)                                             
      Fibrosis                                                                                1 (2%)                                
      Inflammation, Acute                                           1 (2%)       1 (2%)                                             
      Inflammation, Chronic                            1 (2%)                                 1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       2 (4%)       1 (2%)                                
      Mineralization                                                                          1 (2%)                                
   Testes                                             (49)         (49)         (49)         (48)                                   
      Atrophy                                          2 (4%)                                                                       
      Necrosis                                         1 (2%)                                                                       
      Thrombosis                                                                 1 (2%)                                             
      Bilateral, Interstitial Cell, Hyperplasia        3 (6%)       2 (4%)       3 (6%)       1 (2%)                                
      Interstitial Cell, Hyperplasia                   9 (18%)      6 (12%)      6 (12%)      4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Depletion Cellular                               2 (4%)       4 (8%)       3 (6%)       1 (2%)                                
      Fibrosis                                                                   1 (2%)       1 (2%)                                
      Hemorrhage                                                    1 (2%)                                                          
   Lymph Node                                         (20)         (25)         (20)         (23)                                   
      Iliac, Hyperplasia, Lymphoid                     1 (5%)       1 (4%)                                                          
      Iliac, Infiltration Cellular, Plasma Cell        1 (5%)                                                                       
      Mediastinal, Congestion                                       5 (20%)                   4 (17%)                               
      Mediastinal, Ectasia                                                       1 (5%)                                             
      Mediastinal, Hemorrhage                          1 (5%)       1 (4%)       2 (10%)                                            
      Mediastinal, Hyperplasia, Lymphoid                                                      1 (4%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   12                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Mediastinal, Pigmentation                                                  1 (5%)                                             
      Pancreatic, Congestion                                                     1 (5%)       2 (9%)                                
      Pancreatic, Edema                                                                       1 (4%)                                
      Pancreatic, Hyperplasia, Lymphoid                                          1 (5%)                                             
      Pancreatic, Inflammation, Chronic Active                                                1 (4%)                                
      Pancreatic, Necrosis                                                       1 (5%)                                             
      Pancreatic, Pigmentation                                                   1 (5%)                                             
      Renal, Congestion                                1 (5%)                    1 (5%)       3 (13%)                               
      Renal, Edema                                                               1 (5%)                                             
      Renal, Fibrosis                                               1 (4%)                                                          
      Renal, Hyperplasia, Lymphoid                                               2 (10%)                                            
      Renal, Pigmentation                                                        1 (5%)       4 (17%)                               
   Lymph Node, Mandibular                             (50)         (50)         (50)         (50)                                   
      Congestion                                                    1 (2%)       1 (2%)                                             
      Ectasia                                          4 (8%)       3 (6%)       2 (4%)       3 (6%)                                
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Inflammation, Chronic Active                                  1 (2%)                                                          
   Lymph Node, Mesenteric                             (50)         (47)         (50)         (48)                                   
      Congestion                                                    2 (4%)                    1 (2%)                                
      Ectasia                                          2 (4%)       3 (6%)       2 (4%)       1 (2%)                                
      Fibrosis                                                                   2 (4%)                                             
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Inflammation, Acute                              1 (2%)                                                                       
      Necrosis                                                      3 (6%)                                                          
   Spleen                                             (49)         (48)         (50)         (49)                                   
      Atrophy                                                                    1 (2%)                                             
      Congestion                                                    1 (2%)                    1 (2%)                                
      Fibrosis                                        14 (29%)     11 (23%)      9 (18%)     12 (24%)                               
      Hematopoietic Cell Proliferation                 1 (2%)       1 (2%)                    1 (2%)                                
      Hyperplasia, Focal                                                         1 (2%)                                             
      Necrosis                                         4 (8%)       2 (4%)       1 (2%)                                             
      Pigmentation                                                                            2 (4%)                                
      Thrombosis                                                    1 (2%)                                                          
   Thymus                                             (50)         (49)         (48)         (50)                                   
      Cyst                                             1 (2%)                                                                       
      Ectopic Parathyroid Gland                                                               1 (2%)                                
      Fibrosis                                                      1 (2%)                                                          
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (48)         (50)         (49)                                   
      Concretion                                                    1 (2%)                                                          
      Galactocele                                                                1 (2%)                                             
      Hyperplasia                                      1 (2%)       3 (6%)       2 (4%)       3 (6%)                                
      Duct, Dilatation                                14 (29%)     16 (33%)     12 (24%)     15 (31%)                               

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   13                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
   Skin                                               (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                                                  2 (4%)                                             
      Hyperkeratosis                                                             1 (2%)                                             
      Hyperplasia, Squamous                                         1 (2%)       1 (2%)                                             
      Inflammation, Acute                                           1 (2%)                                                          
      Necrosis                                                                   1 (2%)                                             
      Epidermis, Degeneration                                                                 1 (2%)                                
      Subcutaneous Tissue, Inflammation, Chronic                                                                                    
          Active                                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                           2 (4%)       1 (2%)       4 (8%)       6 (12%)                               
      Hyperostosis                                                  1 (2%)                                                          
      Osteomalacia                                                                            1 (2%)                                
      Osteopetrosis                                    1 (2%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (48)         (50)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Hydrocephalus                                    1 (2%)                                                                       
      Inflammation, Acute                                                                     1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                                    1 (2%)                    2 (4%)                                
      Hemorrhage                                                                 2 (4%)       2 (4%)                                
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                                                          
      Infiltration Cellular, Histiocyte                6 (12%)      4 (8%)       9 (18%)      9 (18%)                               
      Inflammation, Chronic                            8 (16%)     10 (20%)     12 (24%)      9 (18%)                               
      Metaplasia, Osseous                                                                     1 (2%)                                
      Alveolar Epithelium, Hyperplasia                              3 (6%)                    3 (6%)                                
   Nose                                               (50)         (50)         (49)         (50)                                   
      Cyst                                                          1 (2%)       1 (2%)                                             
      Cyst Epithelial Inclusion                                                               1 (2%)                                
      Inflammation, Chronic                                                      1 (2%)                                             
      Inflammation, Chronic Active                    26 (52%)     18 (36%)     21 (43%)     25 (50%)                               
      Polyp Inflammatory                                                                      1 (2%)                                
      Nasolacrimal Duct, Cyst                                                    1 (2%)       1 (2%)                                
      Nasolacrimal Duct, Inflammation, Acute           1 (2%)                                 1 (2%)                                
      Squamous Epithelium, Nasolacrimal Duct,                                                                                       

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   14                                                              
NTP Experiment-Test: 55301-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:05:00  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 PPM        100 PPM      200 PPM      400 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
          Hyperplasia                                               1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                             (1)                                                              
      Atrophy                                                       1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (48)         (50)         (49)                                   
      Atrophy                                                                    1 (2%)                                             
      Cyst                                             3 (6%)       3 (6%)      13 (26%)     10 (20%)                               
      Developmental Malformation                       2 (4%)                                                                       
      Hydronephrosis                                   3 (6%)       1 (2%)                    2 (4%)                                
      Inflammation, Acute                                                                     1 (2%)                                
      Nephropathy                                     47 (94%)     47 (98%)     49 (98%)     49 (100%)                              
      Pigmentation                                                                            1 (2%)                                
      Artery, Inflammation, Acute                      1 (2%)                                                                       
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
      Capsule, Hemorrhage, Chronic                                  1 (2%)                                                          
      Pelvis, Inflammation, Acute                                                             1 (2%)                                
      Renal Tubule, Hyperplasia                        1 (2%)                    4 (8%)       7 (14%)                               
   Urinary Bladder                                    (50)         (47)         (50)         (49)                                   
      Hemorrhage                                                    1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic                            4 (8%)                    1 (2%)       1 (2%)                                
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             

                                                             Page   15                                                              
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                             ----------              END OF REPORT             ----------                                           
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