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TDMS Study 05136-07 Pathology Tables

NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  0000126-99-8

       Lock Date:  05/04/94

       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: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                19           21           23           27                                     
    Natural Death                                      1            1            1            2                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                29           28           26           21                                     
  Other                                                1                                                                            
  Animals Examined Microscopically                    49           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (49)         (49)         (50)         (49)                                   
      Parasite Metazoan                                4 (8%)                    6 (12%)      2 (4%)                                
   Intestine Large, Rectum                            (49)         (49)         (50)         (50)                                   
      Inflammation, Acute                                           1 (2%)                                                          
      Mineralization                                   2 (4%)                                 1 (2%)                                
      Parasite Metazoan                                2 (4%)       5 (10%)      7 (14%)      2 (4%)                                
   Intestine Large, Cecum                             (48)         (49)         (50)         (49)                                   
      Inflammation, Acute                              1 (2%)       1 (2%)                                                          
      Parasite Metazoan                                5 (10%)      4 (8%)       8 (16%)      5 (10%)                               
   Intestine Small, Jejunum                           (49)         (49)         (49)         (48)                                   
      Inflammation, Chronic Active                                                            1 (2%)                                
   Intestine Small, Ileum                             (48)         (49)         (49)         (48)                                   
      Parasite Metazoan                                1 (2%)                    1 (2%)                                             
   Liver                                              (49)         (50)         (50)         (50)                                   
      Angiectasis                                      3 (6%)       7 (14%)      5 (10%)      8 (16%)                               
      Basophilic Focus                                39 (80%)     43 (86%)     45 (90%)     44 (88%)                               
      Clear Cell Focus                                15 (31%)     16 (32%)     14 (28%)      6 (12%)                               
      Degeneration, Cystic                                                                    2 (4%)                                
      Degeneration, Fatty                              5 (10%)      5 (10%)      3 (6%)       3 (6%)                                
      Eosinophilic Focus                               2 (4%)                    1 (2%)       2 (4%)                                
      Hepatodiaphragmatic Nodule                       4 (8%)       7 (14%)      9 (18%)      9 (18%)                               
      Mixed Cell Focus                                 7 (14%)      6 (12%)      6 (12%)      9 (18%)                               
      Necrosis                                         1 (2%)       1 (2%)                    2 (4%)                                
      Bile Duct, Hyperplasia                           9 (18%)     10 (20%)     11 (22%)     16 (32%)                               
      Centrilobular, Necrosis                          1 (2%)       3 (6%)       5 (10%)      8 (16%)                               
   Mesentery                                          (5)          (6)          (8)          (11)                                   
      Inflammation, Chronic Active                     1 (20%)                                1 (9%)                                
      Fat, Necrosis                                    4 (80%)      6 (100%)     7 (88%)      9 (82%)                               
   Pancreas                                           (49)         (50)         (50)         (50)                                   
      Atrophy                                         18 (37%)     14 (28%)     17 (34%)      9 (18%)                               
      Basophilic Focus                                 1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
      Hyperplasia                                                   2 (4%)       1 (2%)       2 (4%)                                
      Lipomatosis                                                   1 (2%)       2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Metaplasia, Hepatocyte                                                     1 (2%)                                             
      Artery, Inflammation                                                                    1 (2%)                                
   Salivary Glands                                    (49)         (50)         (50)         (50)                                   
      Atrophy                                                                    1 (2%)       3 (6%)                                
      Basophilic Focus                                                           1 (2%)                                             
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
      Hyperplasia, Squamous                            1 (2%)                    1 (2%)       3 (6%)                                
      Mineralization                                   1 (2%)                                 1 (2%)                                
      Necrosis                                                      2 (4%)       3 (6%)       1 (2%)                                
      Ulcer                                            1 (2%)                    1 (2%)                                             
   Stomach, Glandular                                 (49)         (50)         (50)         (50)                                   
      Mineralization                                   1 (2%)       1 (2%)       4 (8%)       3 (6%)                                
      Necrosis                                                                   1 (2%)                                             
   Tongue                                             (1)          (4)          (5)          (12)                                   
      Hyperplasia, Squamous                            1 (100%)     1 (25%)      1 (20%)      1 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (49)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  38 (78%)     38 (76%)     31 (62%)     41 (82%)                               
      Artery, Inflammation, Chronic                    1 (2%)                                 1 (2%)                                
      Atrium, Thrombosis                                            1 (2%)                                                          
      Schwann Cell, Hyperplasia                                                               1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (50)         (50)         (50)                                   
      Atrophy                                                       1 (2%)                                                          
      Hyperplasia                                     23 (47%)     22 (44%)     22 (44%)     20 (40%)                               
      Hypertrophy                                      8 (16%)     10 (20%)      7 (14%)     10 (20%)                               
      Necrosis                                         2 (4%)                    1 (2%)                                             
      Vacuolization Cytoplasmic                        9 (18%)      5 (10%)     10 (20%)      8 (16%)                               
   Adrenal Medulla                                    (49)         (50)         (50)         (50)                                   
      Hyperplasia                                      7 (14%)     11 (22%)      7 (14%)     10 (20%)                               
   Islets, Pancreatic                                 (49)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       1 (2%)       3 (6%)                                             
   Parathyroid Gland                                  (48)         (50)         (50)         (48)                                   
      Fibrosis                                                      1 (2%)                                                          
      Hyperplasia                                                   2 (4%)                    1 (2%)                                
   Pituitary Gland                                    (48)         (50)         (50)         (50)                                   
      Pars Distalis, Hyperplasia                       9 (19%)      5 (10%)      3 (6%)      10 (20%)                               
   Thyroid Gland                                      (49)         (50)         (50)         (50)                                   
      Fibrosis                                                      1 (2%)                                                          
      C-Cell, Hyperplasia                             38 (78%)     38 (76%)     35 (70%)     28 (56%)                               
      Follicular Cell, Hyperplasia                                                            2 (4%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (46)         (48)         (46)         (46)                                   
      Hyperplasia                                      2 (4%)       1 (2%)       4 (9%)       4 (9%)                                
      Inflammation, Chronic Active                     4 (9%)       4 (8%)       6 (13%)      4 (9%)                                
   Ovary                                              (49)         (50)         (50)         (50)                                   
      Cyst                                             7 (14%)      6 (12%)      1 (2%)       3 (6%)                                
      Inflammation, Granulomatous                      2 (4%)       1 (2%)       1 (2%)                                             
   Uterus                                             (49)         (50)         (50)         (50)                                   
      Hydrometra                                                                 1 (2%)                                             
      Cervix, Hypertrophy                                           1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
      Atrophy                                          3 (6%)                                 1 (2%)                                
      Hyperplasia, Histiocytic                                                   2 (4%)                                             
   Lymph Node                                         (1)          (4)          (4)          (5)                                    
      Iliac, Ectasia                                                             1 (25%)      1 (20%)                               
      Renal, Infiltration Cellular, Plasma Cell                     1 (25%)                                                         
   Lymph Node, Mandibular                             (44)         (48)         (37)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
   Spleen                                             (48)         (50)         (50)         (50)                                   
      Accessory Spleen                                              1 (2%)                    1 (2%)                                
      Angiectasis                                                                             1 (2%)                                
      Fibrosis                                         3 (6%)       1 (2%)       3 (6%)       5 (10%)                               
      Hematopoietic Cell Proliferation                 1 (2%)       4 (8%)       4 (8%)       6 (12%)                               
      Hemorrhage                                       4 (8%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (50)         (50)         (50)                                   
      Galactocele                                      1 (2%)       1 (2%)       2 (4%)                                             
   Skin                                               (49)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                                                               1 (2%)                                
      Hyperkeratosis                                   1 (2%)                                                                       
      Inflammation, Acute                              1 (2%)                                                                       
      Inflammation, Chronic Active                     3 (6%)       5 (10%)      2 (4%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (49)         (50)         (50)         (50)                                   
      Fracture                                                                                1 (2%)                                
      Hyperostosis                                     4 (8%)       5 (10%)      4 (8%)       3 (6%)                                
      Hyperplasia                                                                             1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (49)         (50)         (50)         (50)                                   
      Hemorrhage                                                                 1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (49)         (50)         (50)         (50)                                   
      Congestion, Chronic                                           1 (2%)                                                          
      Hemorrhage                                                    1 (2%)                                                          
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Alveolar Epithelium, Hyperplasia                 6 (12%)     22 (44%)     22 (44%)     34 (68%)                               
      Artery, Mediastinum, Inflammation                                                       1 (2%)                                
   Nose                                               (49)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                        1 (2%)       2 (4%)                                                          
      Thrombosis                                                    1 (2%)       1 (2%)       3 (6%)                                
      Nasolacrimal Duct, Hyperplasia, Squamous                                                1 (2%)                                
      Olfactory Epithelium, Atrophy                                 1 (2%)      40 (80%)     50 (100%)                              
      Olfactory Epithelium, Fibrosis                                                         49 (98%)                               
      Olfactory Epithelium, Hyperplasia, Basal Cell                             17 (34%)     49 (98%)                               
      Olfactory Epithelium, Hyperplasia,                                                                                            
          Adenomatous                                                                        27 (54%)                               
      Olfactory Epithelium, Inflammation, Chronic                                                                                   
          Active                                                                 2 (4%)      33 (66%)                               
      Olfactory Epithelium, Metaplasia                              1 (2%)      35 (70%)     50 (100%)                              
      Olfactory Epithelium, Necrosis                                             8 (16%)     12 (24%)                               
      Olfactory Epithelium, Glands, Atypia Cellular                                           2 (4%)                                
      Turbinate, Fibrosis, Focal                                    1 (2%)       3 (6%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (1)          (3)          (2)                                    
      Cataract                                         1 (100%)                  2 (67%)      2 (100%)                              
      Degeneration                                                  1 (100%)                                                        
      Retina, Atrophy                                                            2 (67%)      2 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Hydronephrosis                                   1 (2%)                                                                       
      Hyperplasia, Oncocytic                                                                  1 (2%)                                
      Infarct                                                       1 (2%)                    1 (2%)                                
      Mineralization                                                                          1 (2%)                                
      Nephropathy                                     43 (88%)     48 (96%)     49 (98%)     49 (98%)                               
      Artery, Inflammation                                                                    1 (2%)                                
      Pelvis, Inflammation, Acute                                                             1 (2%)                                
      Renal Tubule, Hyperplasia                                                  1 (2%)       4 (8%)                                
   Urinary Bladder                                    (49)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)                                                                       
      Transitional Epithelium, Hyperplasia                                       1 (2%)       1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                34           40           41           41                                     
    Natural Death                                      3            1            4            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                13            9            5            4                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (49)         (48)         (49)                                   
      Mineralization                                   1 (2%)                                                                       
      Parasite Metazoan                                4 (8%)       7 (14%)                   3 (6%)                                
   Intestine Large, Rectum                            (50)         (47)         (50)         (49)                                   
      Mineralization                                                1 (2%)       1 (2%)                                             
      Parasite Metazoan                                2 (4%)       1 (2%)       2 (4%)                                             
   Intestine Large, Cecum                             (48)         (49)         (46)         (48)                                   
      Necrosis                                         1 (2%)                                                                       
      Parasite Metazoan                               10 (21%)      7 (14%)      7 (15%)      6 (13%)                               
   Intestine Small, Duodenum                          (50)         (49)         (49)         (50)                                   
      Necrosis                                                                   1 (2%)                                             
   Liver                                              (50)         (50)         (49)         (50)                                   
      Angiectasis                                      2 (4%)       5 (10%)      6 (12%)      5 (10%)                               
      Basophilic Focus                                16 (32%)     17 (34%)     21 (43%)     13 (26%)                               
      Clear Cell Focus                                 8 (16%)      6 (12%)      3 (6%)       2 (4%)                                
      Degeneration, Cystic                            13 (26%)     18 (36%)     20 (41%)     21 (42%)                               
      Degeneration, Fatty                              3 (6%)       4 (8%)       4 (8%)       3 (6%)                                
      Eosinophilic Focus                                                         3 (6%)       4 (8%)                                
      Hepatodiaphragmatic Nodule                       2 (4%)       1 (2%)       4 (8%)       3 (6%)                                
      Inflammation, Chronic                                         1 (2%)                                                          
      Mixed Cell Focus                                              1 (2%)       2 (4%)       1 (2%)                                
      Necrosis                                                      2 (4%)       1 (2%)       1 (2%)                                
      Regeneration                                     2 (4%)       3 (6%)       3 (6%)                                             
      Thrombosis                                                                 1 (2%)                                             
      Bile Duct, Hyperplasia                          36 (72%)     40 (80%)     35 (71%)     34 (68%)                               
      Centrilobular, Necrosis                         13 (26%)     13 (26%)     13 (27%)      8 (16%)                               
   Mesentery                                          (16)         (13)         (18)         (13)                                   
      Inflammation, Chronic Active                     1 (6%)       1 (8%)                    1 (8%)                                
      Artery, Mineralization                                                     1 (6%)                                             
      Fat, Hemorrhage                                  1 (6%)                                                                       
      Fat, Necrosis                                   15 (94%)     13 (100%)    14 (78%)     11 (85%)                               
   Oral Mucosa                                                     (2)          (1)          (7)                                    
      Pharyngeal, Hyperplasia, Squamous                                                       3 (43%)                               
   Pancreas                                           (50)         (50)         (49)         (50)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Atrophy                                         27 (54%)     27 (54%)     30 (61%)     23 (46%)                               
      Basophilic Focus                                 2 (4%)       2 (4%)       2 (4%)       1 (2%)                                
      Hyperplasia                                      7 (14%)      3 (6%)       5 (10%)      1 (2%)                                
      Artery, Inflammation                                                       2 (4%)                                             
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                                                                 1 (2%)                                
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Hyperplasia, Squamous                            2 (4%)       1 (2%)       2 (4%)       1 (2%)                                
      Inflammation, Chronic Active                                                            5 (10%)                               
      Mineralization                                   1 (2%)       1 (2%)       1 (2%)                                             
      Necrosis                                         2 (4%)       5 (10%)      2 (4%)       3 (6%)                                
      Ulcer                                            1 (2%)       1 (2%)       6 (12%)     11 (22%)                               
   Stomach, Glandular                                 (49)         (50)         (49)         (50)                                   
      Mineralization                                   5 (10%)      5 (10%)      3 (6%)       5 (10%)                               
      Necrosis                                         2 (4%)       2 (4%)       6 (12%)      2 (4%)                                
   Tooth                                                           (2)                                                              
      Developmental Malformation                                    1 (50%)                                                         
      Inflammation, Chronic Active                                  2 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                 (3)          (1)                                    
      Aorta, Mineralization                                                      2 (67%)      1 (100%)                              
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  43 (86%)     46 (92%)     39 (78%)     45 (90%)                               
      Artery, Mineralization                                                     2 (4%)                                             
      Atrium, Thrombosis                               1 (2%)       1 (2%)       4 (8%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (49)         (50)                                   
      Atrophy                                                       1 (2%)                                                          
      Hyperplasia                                     23 (46%)     25 (50%)     26 (53%)     23 (46%)                               
      Hypertrophy                                      1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Necrosis                                                      2 (4%)       1 (2%)       2 (4%)                                
      Vacuolization Cytoplasmic                        1 (2%)       4 (8%)       3 (6%)       2 (4%)                                
   Adrenal Medulla                                    (50)         (50)         (49)         (50)                                   
      Hyperplasia                                     23 (46%)     19 (38%)     19 (39%)     17 (34%)                               
      Necrosis                                                      1 (2%)                                                          
   Islets, Pancreatic                                 (50)         (50)         (49)         (50)                                   
      Hyperplasia                                      3 (6%)       2 (4%)       3 (6%)       3 (6%)                                
   Parathyroid Gland                                  (48)         (49)         (50)         (50)                                   
      Hyperplasia                                      5 (10%)     10 (20%)     19 (38%)     24 (48%)                               
   Pituitary Gland                                    (50)         (49)         (50)         (49)                                   
      Pars Distalis, Cyst                                           1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Distalis, Hyperplasia                       7 (14%)      4 (8%)       5 (10%)      2 (4%)                                
      Pars Intermedia, Hyperplasia                                  1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (49)         (50)                                   
      C-Cell, Hyperplasia                             34 (68%)     24 (48%)     23 (47%)     28 (56%)                               
      Follicular Cell, Hyperplasia                                  2 (4%)       4 (8%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                  (1)                                                                           
      Hyperplasia                                      1 (100%)                                                                     
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  2 (4%)       3 (6%)       1 (2%)                                             
      Hyperplasia                                                   2 (4%)       6 (12%)      1 (2%)                                
      Necrosis, Fatty                                                            1 (2%)                                             
   Penis                                              (1)          (3)                                                              
      Vein, Fibrosis                                                1 (33%)                                                         
   Preputial Gland                                    (50)         (50)         (48)         (50)                                   
      Hyperplasia                                      4 (8%)       3 (6%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     9 (18%)      6 (12%)      3 (6%)       4 (8%)                                
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      7 (14%)      7 (14%)      5 (10%)      4 (8%)                                
      Inflammation, Chronic Active                     2 (4%)       4 (8%)       4 (8%)       5 (10%)                               
      Mineralization                                   1 (2%)                                                                       
   Seminal Vesicle                                    (50)         (50)         (50)         (49)                                   
      Amyloid Deposition                                                         1 (2%)                                             
      Inflammation, Chronic Active                                                            1 (2%)                                
      Mineralization                                                             1 (2%)                                             
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)       4 (8%)       4 (8%)       1 (2%)                                
      Hyperplasia                                                   1 (2%)                                                          
      Artery, Inflammation, Chronic Active             2 (4%)       2 (4%)       4 (8%)       3 (6%)                                
      Interstitial Cell, Hyperplasia                  10 (20%)      4 (8%)       9 (18%)      7 (14%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Necrosis                                         1 (2%)                                                                       
   Lymph Node                                         (12)         (18)         (11)         (15)                                   
      Iliac, Ectasia                                                1 (6%)                                                          
      Pancreatic, Hemorrhage                                                     1 (9%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Renal, Ectasia                                                                          1 (7%)                                
      Renal, Hemorrhage                                1 (8%)       2 (11%)      3 (27%)      5 (33%)                               
      Renal, Infiltration Cellular, Plasma Cell                                  1 (9%)                                             
      Renal, Pigmentation                                                                     1 (7%)                                
   Lymph Node, Mandibular                             (47)         (45)         (44)         (49)                                   
      Ectasia                                          1 (2%)                                                                       
      Hemorrhage                                                                 1 (2%)                                             
      Infiltration Cellular, Plasma Cell                            2 (4%)                    1 (2%)                                
   Lymph Node, Mesenteric                             (50)         (50)         (48)         (50)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Infiltration Cellular, Plasma Cell                                                      1 (2%)                                
   Lymph Node, Mediastinal                            (46)         (47)         (48)         (47)                                   
      Hemorrhage                                                                 1 (2%)                                             
   Spleen                                             (50)         (50)         (49)         (50)                                   
      Accessory Spleen                                 2 (4%)       1 (2%)       1 (2%)                                             
      Fibrosis                                        17 (34%)     19 (38%)     17 (35%)     20 (40%)                               
      Hematopoietic Cell Proliferation                 2 (4%)       2 (4%)       3 (6%)       6 (12%)                               
      Hemorrhage                                       1 (2%)       1 (2%)                                                          
      Metaplasia, Lipocyte                                          1 (2%)                                                          
      Necrosis                                         1 (2%)       2 (4%)       3 (6%)                                             
      Thrombosis                                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (30)         (23)         (30)         (28)                                   
      Galactocele                                      4 (13%)      3 (13%)      3 (10%)      1 (4%)                                
      Inflammation, Chronic                            1 (3%)                                                                       
   Skin                                               (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 (2%)                                                                       
      Hyperkeratosis                                                2 (4%)                    1 (2%)                                
      Inflammation, Chronic Active                     3 (6%)       4 (8%)       8 (16%)      5 (10%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                                        4 (8%)       7 (14%)     11 (22%)                               
      Hyperplasia                                                   1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Hydrocephalus                                                                           1 (2%)                                
      Mineralization                                                                          1 (2%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
NERVOUS SYSTEM - CONT                                                                                                               
      Necrosis                                                      1 (2%)       2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (50)                                   
      Inflammation, Acute                              1 (2%)                                 1 (2%)                                
   Lung                                               (50)         (50)         (49)         (50)                                   
      Foreign Body                                                                            1 (2%)                                
      Hemorrhage                                       1 (2%)       2 (4%)       1 (2%)       1 (2%)                                
      Infiltration Cellular                            1 (2%)                                                                       
      Inflammation, Chronic Active                                               1 (2%)       1 (2%)                                
      Metaplasia, Cartilagenous                        1 (2%)                                                                       
      Metaplasia, Osseous                                           1 (2%)                                                          
      Mineralization                                                1 (2%)       1 (2%)       1 (2%)                                
      Thrombosis                                       1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia                 5 (10%)     16 (32%)     14 (29%)     25 (50%)                               
      Artery, Mediastinum, Mineralization                                        1 (2%)       2 (4%)                                
   Nose                                               (50)         (50)         (49)         (49)                                   
      Cyst                                                                                    1 (2%)                                
      Inflammation, Suppurative                        1 (2%)       1 (2%)       4 (8%)                                             
      Thrombosis                                      10 (20%)      9 (18%)      3 (6%)       2 (4%)                                
      Olfactory Epithelium, Atrophy                    3 (6%)      12 (24%)     46 (94%)     48 (98%)                               
      Olfactory Epithelium, Fibrosis                                                         47 (96%)                               
      Olfactory Epithelium, Hyperplasia, Basal Cell                             38 (78%)     46 (94%)                               
      Olfactory Epithelium, Hyperplasia,                                                                                            
          Adenomatous                                  2 (4%)                    1 (2%)      42 (86%)                               
      Olfactory Epithelium, Inflammation, Chronic                                                                                   
          Active                                                    5 (10%)      9 (18%)     49 (100%)                              
      Olfactory Epithelium, Metaplasia                 6 (12%)      5 (10%)     45 (92%)     48 (98%)                               
      Olfactory Epithelium, Necrosis                               11 (22%)     26 (53%)     19 (39%)                               
      Respiratory Epithelium, Hyperplasia                                                     1 (2%)                                
      Turbinate, Fibrosis, Focal                                                 5 (10%)                                            
   Trachea                                            (50)         (50)         (50)         (50)                                   
      Mineralization                                                             1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                                                       (1)                                    
      External Ear, Inflammation, Chronic Active                                              1 (100%)                              
   Eye                                                             (1)          (1)                                                 
      Cataract                                                                   1 (100%)                                           
      Retina, Atrophy                                               1 (100%)     1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05136-07         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:05:20  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             3 (6%)       3 (6%)       3 (6%)       5 (10%)                               
      Hyperplasia, Oncocytic                                                                  2 (4%)                                
      Infarct                                                       2 (4%)       2 (4%)                                             
      Mineralization                                   1 (2%)                    2 (4%)       1 (2%)                                
      Nephropathy                                     50 (100%)    50 (100%)    50 (100%)    50 (100%)                              
      Pelvis, Inflammation, Acute                                                             1 (2%)                                
      Renal Tubule, Hyperplasia                        2 (4%)       3 (6%)       6 (12%)      6 (12%)                               
      Transitional Epithelium, Hyperplasia                                                    1 (2%)                                
   Urinary Bladder                                    (50)         (50)         (50)         (49)                                   
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Infiltration Cellular                            1 (2%)                                                                       
      Inflammation, Chronic Active                                  2 (4%)       1 (2%)       1 (2%)                                
      Transitional Epithelium, Hyperplasia                          1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
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                             ----------              END OF REPORT             ----------                                           
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