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https://ntp.niehs.nih.gov/go/2964

TDMS Study 05136-08 Pathology Tables

NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  0000126-99-8

       Lock Date:  04/14/94

       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: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                13           27           38           41                                     
    Natural Death                                      2            6           11            5                                     
    Accidently Killed                                               1                         1                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                35           16            1            2                                     
    Moribund Sacrifice                                                                        1                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (49)         (48)         (50)         (50)                                   
      Epithelium, Hyperplasia                                       1 (2%)                                                          
   Gallbladder                                        (45)         (44)         (42)         (42)                                   
      Angiectasis                                      1 (2%)                                                                       
      Cyst                                             1 (2%)                                                                       
      Degeneration, Hyaline                                                      2 (5%)                                             
      Inflammation, Suppurative                        3 (7%)       1 (2%)       2 (5%)       2 (5%)                                
      Necrosis                                         1 (2%)                                                                       
   Intestine Large, Colon                             (50)         (47)         (48)         (49)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
   Intestine Large, Cecum                             (50)         (45)         (45)         (49)                                   
      Hemorrhage                                                                              1 (2%)                                
      Lymphoid Tissue, Hyperplasia                                  1 (2%)       1 (2%)                                             
   Intestine Small, Duodenum                          (49)         (45)         (42)         (48)                                   
      Necrosis                                                                                1 (2%)                                
      Epithelium, Hyperplasia                                                                 1 (2%)                                
   Intestine Small, Jejunum                           (50)         (46)         (44)         (49)                                   
      Epithelium, Hyperplasia                          1 (2%)                                                                       
      Peyer's Patch, Hyperplasia                       1 (2%)                    1 (2%)                                             
   Liver                                              (50)         (49)         (50)         (50)                                   
      Angiectasis                                      2 (4%)       3 (6%)       4 (8%)       1 (2%)                                
      Basophilic Focus                                 4 (8%)                                 2 (4%)                                
      Clear Cell Focus                                 1 (2%)                                                                       
      Degeneration, Fatty                              1 (2%)                    2 (4%)                                             
      Eosinophilic Focus                              13 (26%)     12 (24%)     15 (30%)     28 (56%)                               
      Fibrosis                                         1 (2%)                                                                       
      Hematopoietic Cell Proliferation                 1 (2%)       5 (10%)      9 (18%)     12 (24%)                               
      Hyperplasia, Lymphoid                                                                   1 (2%)                                
      Inflammation, Chronic                                         1 (2%)                                                          
      Mineralization                                                             1 (2%)       1 (2%)                                
      Necrosis                                         4 (8%)       5 (10%)     13 (26%)      7 (14%)                               
      Regeneration                                                                            1 (2%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Vacuolization Cytoplasmic                                     2 (4%)                    1 (2%)                                
      Bile Duct, Cyst                                  1 (2%)                                 1 (2%)                                
      Bile Duct, Hyperplasia                           2 (4%)       1 (2%)       1 (2%)       3 (6%)                                
      Centrilobular, Degeneration                                                2 (4%)       3 (6%)                                
      Centrilobular, Necrosis                                       2 (4%)       2 (4%)       3 (6%)                                
   Mesentery                                          (10)         (14)         (27)         (21)                                   
      Angiectasis                                      1 (10%)                                1 (5%)                                
      Hemorrhage                                                                 1 (4%)                                             
      Fat, Inflammation, Chronic                                    1 (7%)                                                          
      Fat, Necrosis                                    7 (70%)      3 (21%)      2 (7%)      18 (86%)                               
   Oral Mucosa                                        (1)                                                                           
      Pharyngeal, Hyperplasia                          1 (100%)                                                                     
   Pancreas                                           (49)         (49)         (48)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Atrophy                                          3 (6%)       6 (12%)      5 (10%)      3 (6%)                                
      Hyperplasia                                                                             1 (2%)                                
      Hypertrophy                                      2 (4%)       3 (6%)       3 (6%)       4 (8%)                                
      Duct, Cyst                                                                              1 (2%)                                
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
      Inflammation                                                  1 (2%)                                                          
   Stomach, Forestomach                               (50)         (49)         (49)         (50)                                   
      Diverticulum                                                  2 (4%)                                                          
      Hyperplasia                                                                             3 (6%)                                
      Inflammation, Suppurative                        2 (4%)                                 8 (16%)                               
      Mineralization                                   1 (2%)                                                                       
      Ulcer                                                         2 (4%)       3 (6%)       5 (10%)                               
      Epithelium, Hyperplasia                          4 (8%)       3 (6%)       8 (16%)     27 (54%)                               
   Stomach, Glandular                                 (50)         (48)         (49)         (50)                                   
      Degeneration, Hyaline                                                                   1 (2%)                                
      Inflammation, Suppurative                                                               4 (8%)                                
      Necrosis                                                                   3 (6%)                                             
      Epithelium, Hyperplasia                                                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (2)                                                                           
      Hyperplasia                                      1 (50%)                                                                      
      Inflammation                                     1 (50%)                                                                      
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                  35 (70%)     35 (71%)     34 (68%)     33 (66%)                               
      Mineralization                                                             1 (2%)                                             
      Artery, Inflammation                                                                    1 (2%)                                
      Atrium, Thrombosis                                            1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (48)         (49)         (50)                                   
      Hematopoietic Cell Proliferation                 1 (2%)                    2 (4%)       1 (2%)                                
      Hyperplasia                                      1 (2%)                                                                       
      Hypertrophy                                      2 (4%)       2 (4%)       3 (6%)       2 (4%)                                
      Inflammation, Focal, Granulomatous                                         1 (2%)                                             
      Necrosis                                                                                1 (2%)                                
      Capsule, Hyperplasia                                          1 (2%)                                                          
   Adrenal Medulla                                    (50)         (48)         (48)         (50)                                   
      Hyperplasia                                      3 (6%)       2 (4%)                    1 (2%)                                
      Necrosis                                                                                1 (2%)                                
   Islets, Pancreatic                                 (49)         (49)         (48)         (50)                                   
      Hyperplasia                                                                1 (2%)       1 (2%)                                
   Pituitary Gland                                    (49)         (48)         (48)         (50)                                   
      Pars Distalis, Angiectasis                                    1 (2%)       1 (2%)                                             
      Pars Distalis, Hyperplasia                      18 (37%)      8 (17%)      7 (15%)      9 (18%)                               
      Pars Intermedia, Hyperplasia                                  1 (2%)                    1 (2%)                                
   Thyroid Gland                                      (50)         (49)         (49)         (50)                                   
      Follicular Cell, Hyperplasia                    12 (24%)     15 (31%)      8 (16%)      4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (48)         (47)         (47)         (49)                                   
      Angiectasis                                                   1 (2%)                                                          
      Atrophy                                          7 (15%)      8 (17%)      7 (15%)      6 (12%)                               
      Cyst                                            20 (42%)     18 (38%)      5 (11%)      6 (12%)                               
      Fibrosis                                                                                1 (2%)                                
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Corpus Luteum, Hyperplasia                                                              1 (2%)                                
      Granulosa Cell, Hyperplasia                                   2 (4%)       1 (2%)                                             
   Uterus                                             (50)         (49)         (50)         (50)                                   
      Angiectasis                                      3 (6%)                    2 (4%)       2 (4%)                                
      Hemorrhage                                       1 (2%)                                 2 (4%)                                
      Hydrometra                                       3 (6%)       6 (12%)      2 (4%)       8 (16%)                               
      Hyperplasia, Cystic                              5 (10%)      3 (6%)       2 (4%)       3 (6%)                                
      Inflammation, Suppurative                        1 (2%)                    2 (4%)                                             
      Endometrium, Hyperplasia                                                                1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (49)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Atrophy                                                       1 (2%)                                                          
      Hyperplasia                                      2 (4%)       2 (4%)       3 (6%)       4 (8%)                                
      Necrosis                                         1 (2%)                                                                       
   Lymph Node                                         (4)          (3)          (5)          (2)                                    
      Hyperplasia                                                                1 (20%)                                            
      Iliac, Hyperplasia                               1 (25%)                   1 (20%)      1 (50%)                               
      Pancreatic, Hyperplasia                          1 (25%)                                                                      
      Renal, Hyperplasia                                            1 (33%)                                                         
   Lymph Node, Bronchial                              (32)         (31)         (34)         (38)                                   
      Congestion                                                    1 (3%)                                                          
      Hematopoietic Cell Proliferation                              1 (3%)       1 (3%)                                             
      Hyperplasia                                      2 (6%)       3 (10%)      4 (12%)      3 (8%)                                
   Lymph Node, Mandibular                             (32)         (40)         (33)         (40)                                   
      Angiectasis                                                   1 (3%)                                                          
      Hematopoietic Cell Proliferation                                                        1 (3%)                                
      Hyperplasia                                      2 (6%)       2 (5%)                    4 (10%)                               
      Infiltration Cellular, Mast Cell                              1 (3%)                                                          
   Lymph Node, Mesenteric                             (48)         (45)         (48)         (46)                                   
      Angiectasis                                      1 (2%)       1 (2%)       1 (2%)                                             
      Congestion                                                                              1 (2%)                                
      Hematopoietic Cell Proliferation                 1 (2%)       2 (4%)                    1 (2%)                                
      Hemorrhage                                                                              1 (2%)                                
      Hyperplasia                                      6 (13%)      1 (2%)       2 (4%)       2 (4%)                                
      Inflammation, Chronic                                                                   1 (2%)                                
   Lymph Node, Mediastinal                            (38)         (44)         (45)         (40)                                   
      Hematopoietic Cell Proliferation                                           1 (2%)                                             
      Hyperplasia                                                   1 (2%)       7 (16%)      7 (18%)                               
   Spleen                                             (50)         (49)         (49)         (50)                                   
      Angiectasis                                      1 (2%)                                                                       
      Hematopoietic Cell Proliferation                13 (26%)     25 (51%)     42 (86%)     39 (78%)                               
      Hyperplasia, Lymphoid                            9 (18%)      5 (10%)      1 (2%)       3 (6%)                                
      Infiltration Cellular, Mononuclear Cell          1 (2%)                                                                       
   Thymus                                             (44)         (35)         (39)         (39)                                   
      Angiectasis                                      1 (2%)       1 (3%)                                                          
      Atrophy                                          1 (2%)                    3 (8%)       1 (3%)                                
      Hyperplasia, Lymphoid                            2 (5%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (49)         (50)         (50)                                   
      Galactocele                                                                             1 (2%)                                
      Hyperplasia                                                   1 (2%)       1 (2%)       3 (6%)                                
   Skin                                               (49)         (49)         (50)         (50)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Inflammation, Chronic Active                     1 (2%)       3 (6%)       1 (2%)                                             
      Sebaceous Gland, Hyperplasia                                                            2 (4%)                                
      Subcutaneous Tissue, Inflammation,                                                                                            
          Suppurative                                  2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (49)         (50)         (50)                                   
      Fibrous Osteodystrophy                          15 (30%)     11 (22%)      6 (12%)      9 (18%)                               
      Fracture                                                                                1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (50)         (50)                                   
      Gliosis                                          1 (2%)                                                                       
      Hemorrhage                                                    1 (2%)                                                          
      Meninges, Inflammation, Chronic                  3 (6%)                                 1 (2%)                                
   Spinal Cord                                        (1)                                                                           
      Degeneration                                     1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       1 (2%)       1 (2%)       5 (10%)                               
      Inflammation, Suppurative                                                  1 (2%)       1 (2%)                                
      Epiglottis, Hyperplasia                                                                 1 (2%)                                
   Lung                                               (50)         (49)         (50)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Hemorrhage                                                    1 (2%)       1 (2%)       1 (2%)                                
      Infiltration Cellular, Histiocyte                1 (2%)      14 (29%)     18 (36%)     23 (46%)                               
      Inflammation, Chronic, Focal                                                            1 (2%)                                
      Thrombosis                                                    1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia                 1 (2%)       1 (2%)       1 (2%)       4 (8%)                                
      Bronchiole, Hyperplasia                                      15 (31%)     12 (24%)     30 (60%)                               
      Perivascular, Infiltration Cellular              1 (2%)                    1 (2%)                                             
   Nose                                               (50)         (49)         (49)         (50)                                   
      Infiltration Cellular, Mast Cell                              1 (2%)                                                          
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Suppurative                                     1 (2%)       3 (6%)       4 (8%)                                
      Metaplasia                                                                              1 (2%)                                
      Nasolacrimal Duct, Inflammation, Suppurative                               1 (2%)                                             
      Olfactory Epithelium, Atrophy                    6 (12%)      5 (10%)      4 (8%)      47 (94%)                               
      Olfactory Epithelium, Degeneration, Hyaline      3 (6%)                                                                       
      Olfactory Epithelium, Hyperplasia,                                                                                            
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
          Adenomatous                                  2 (4%)       3 (6%)                   44 (88%)                               
      Olfactory Epithelium, Metaplasia                 2 (4%)       3 (6%)       1 (2%)      44 (88%)                               
      Olfactory Epithelium, Glands, Inflammation,                                                                                   
           Acute                                                    1 (2%)                                                          
      Respiratory Epithelium, Degeneration, Hyaline   17 (34%)      9 (18%)     10 (20%)     25 (50%)                               
      Respiratory Epithelium, Necrosis                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (1)                                                              
      Inflammation                                                  1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (49)         (49)         (50)                                   
      Hydronephrosis                                   1 (2%)       1 (2%)       4 (8%)                                             
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Metaplasia, Osseous                                           1 (2%)                    1 (2%)                                
      Nephropathy                                     41 (82%)     35 (71%)     25 (51%)     20 (40%)                               
      Pigmentation, Hemosiderin                                     1 (2%)                    3 (6%)                                
      Artery, Inflammation, Chronic                    1 (2%)                                                                       
      Papilla, Necrosis                                                          1 (2%)                                             
      Renal Tubule, Mineralization                     1 (2%)                                                                       
      Renal Tubule, Necrosis                                                     4 (8%)                                             
   Urinary Bladder                                    (50)         (47)         (46)         (47)                                   
      Hemorrhage                                                                 1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                15           16           26           34                                     
    Natural Death                                      8            7           10            3                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                27           27           14           13                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (49)         (50)         (50)                                   
      Dysplasia                                                                               1 (2%)                                
      Inflammation, Suppurative                                                               1 (2%)                                
      Epithelium, Hyperplasia                                                                 1 (2%)                                
   Gallbladder                                        (41)         (40)         (37)         (40)                                   
      Degeneration, Hyaline                            5 (12%)      1 (3%)       2 (5%)       3 (8%)                                
      Inflammation, Suppurative                        1 (2%)                    1 (3%)                                             
      Necrosis                                         1 (2%)                                                                       
      Epithelium, Hyperplasia                          1 (2%)                                                                       
   Intestine Small, Duodenum                          (45)         (44)         (45)         (48)                                   
      Inflammation, Suppurative                                                               1 (2%)                                
      Necrosis                                                      1 (2%)                                                          
   Intestine Small, Jejunum                           (46)         (43)         (47)         (49)                                   
      Peyer's Patch, Hyperplasia                                                              1 (2%)                                
   Intestine Small, Ileum                             (46)         (45)         (46)         (48)                                   
      Peyer's Patch, Hyperplasia                                                 1 (2%)                                             
   Liver                                              (50)         (50)         (50)         (49)                                   
      Angiectasis                                      2 (4%)       3 (6%)                    1 (2%)                                
      Basophilic Focus                                 4 (8%)       2 (4%)                    1 (2%)                                
      Clear Cell Focus                                 1 (2%)       1 (2%)                                                          
      Congestion                                       1 (2%)                                                                       
      Degeneration, Cystic                             1 (2%)       1 (2%)                                                          
      Eosinophilic Focus                               7 (14%)      7 (14%)      3 (6%)       8 (16%)                               
      Hematopoietic Cell Proliferation                 1 (2%)       1 (2%)       1 (2%)       4 (8%)                                
      Karyomegaly                                     19 (38%)     13 (26%)     20 (40%)     29 (59%)                               
      Mitotic Alteration                                                         1 (2%)                                             
      Necrosis                                         9 (18%)      7 (14%)      7 (14%)      6 (12%)                               
      Regeneration                                    22 (44%)     25 (50%)     25 (50%)     27 (55%)                               
      Vacuolization Cytoplasmic                        1 (2%)                                                                       
      Bile Duct, Hyperplasia                          34 (68%)     31 (62%)     34 (68%)     36 (73%)                               
      Centrilobular, Necrosis                                                    1 (2%)                                             
   Mesentery                                          (2)          (8)          (16)         (11)                                   
      Angiectasis                                                                2 (13%)                                            
      Inflammation, Focal, Granulomatous                                                      1 (9%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Thrombosis                                                                              1 (9%)                                
      Fat, Inflammation, Chronic                       1 (50%)      1 (13%)                                                         
      Fat, Necrosis                                    1 (50%)      2 (25%)      1 (6%)       1 (9%)                                
   Pancreas                                           (50)         (48)         (49)         (50)                                   
      Atrophy                                          4 (8%)       4 (8%)       2 (4%)       2 (4%)                                
      Basophilic Focus                                                           1 (2%)                                             
      Cytoplasmic Alteration                                        1 (2%)       1 (2%)                                             
      Hyperplasia                                                                             1 (2%)                                
      Hypertrophy                                      1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Duct, Cyst                                                    1 (2%)                                                          
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
      Inflammation                                     1 (2%)                                                                       
   Stomach, Forestomach                               (50)         (48)         (49)         (50)                                   
      Infiltration Cellular, Mast Cell                              1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)       3 (6%)       5 (10%)                               
      Ulcer                                            2 (4%)       3 (6%)       1 (2%)      12 (24%)                               
      Epithelium, Hyperplasia                          4 (8%)       6 (13%)      7 (14%)     29 (58%)                               
   Stomach, Glandular                                 (50)         (48)         (50)         (48)                                   
      Inflammation, Suppurative                                     1 (2%)       1 (2%)                                             
      Mineralization                                   1 (2%)       1 (2%)                    1 (2%)                                
      Necrosis                                         2 (4%)                    1 (2%)       1 (2%)                                
      Pigmentation                                                               1 (2%)                                             
   Tooth                                              (2)          (2)                                                              
      Developmental Malformation                       2 (100%)     2 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                    (2)          (1)          (1)                                    
      Inflammation                                                               1 (100%)                                           
      Mineralization                                                1 (50%)                                                         
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                  43 (86%)     43 (88%)     40 (80%)     45 (90%)                               
      Hyperplasia, Atypical                                                      1 (2%)                                             
      Inflammation                                                               1 (2%)                                             
      Mineralization                                                             1 (2%)                                             
      Artery, Inflammation                                                       1 (2%)                                             
      Atrium, Thrombosis                               1 (2%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      2 (4%)       4 (8%)       3 (6%)                                             
      Hypertrophy                                     13 (26%)     15 (31%)     12 (24%)      9 (18%)                               
      Capsule, Hyperplasia                             2 (4%)                                 1 (2%)                                
   Adrenal Medulla                                    (50)         (49)         (50)         (49)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hyperplasia                                      3 (6%)       3 (6%)       5 (10%)      2 (4%)                                
   Islets, Pancreatic                                 (50)         (48)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)       2 (4%)       2 (4%)       4 (8%)                                
   Parathyroid Gland                                  (35)         (32)         (31)         (30)                                   
      Hyperplasia                                      1 (3%)                                                                       
   Pituitary Gland                                    (49)         (47)         (47)         (48)                                   
      Pars Distalis, Hyperplasia                       1 (2%)       2 (4%)       1 (2%)                                             
      Pars Intermedia, Hyperplasia                     1 (2%)                                                                       
      Pars Nervosa, Inflammation                                                 1 (2%)                                             
   Thyroid Gland                                      (50)         (49)         (50)         (50)                                   
      Follicular Cell, Hyperplasia                     5 (10%)      5 (10%)      6 (12%)      7 (14%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (49)         (50)         (50)                                   
      Granuloma Sperm                                  3 (6%)                    1 (2%)       1 (2%)                                
      Hyperplasia                                                                1 (2%)                                             
      Inflammation                                                                            1 (2%)                                
   Preputial Gland                                    (50)         (47)         (47)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Cyst                                             2 (4%)       7 (15%)      2 (4%)       3 (6%)                                
      Fibrosis                                                                                1 (2%)                                
      Inflammation                                     2 (4%)       4 (9%)       3 (6%)       1 (2%)                                
   Prostate                                           (49)         (48)         (48)         (49)                                   
      Hyperplasia                                                   1 (2%)                                                          
      Inflammation, Suppurative                        2 (4%)       1 (2%)       2 (4%)                                             
   Seminal Vesicle                                    (49)         (48)         (49)         (48)                                   
      Inflammation                                     2 (4%)       2 (4%)       1 (2%)                                             
   Testes                                             (50)         (49)         (50)         (50)                                   
      Angiectasis                                                                1 (2%)                                             
      Atrophy                                          2 (4%)       3 (6%)       2 (4%)       4 (8%)                                
      Inflammation, Focal, Granulomatous               1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      3 (6%)       1 (2%)       3 (6%)       5 (10%)                               
      Infiltration Cellular, Mast Cell                              1 (2%)                                                          
   Lymph Node                                                      (1)          (2)          (3)                                    
      Iliac, Hyperplasia                                                         2 (100%)                                           
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
   Lymph Node, Bronchial                              (32)         (23)         (33)         (28)                                   
      Hyperplasia                                      4 (13%)      1 (4%)       2 (6%)       1 (4%)                                
   Lymph Node, Mandibular                             (32)         (28)         (27)         (34)                                   
      Hyperplasia                                      2 (6%)       2 (7%)       1 (4%)                                             
      Infiltration Cellular, Mast Cell                              1 (4%)                                                          
   Lymph Node, Mesenteric                             (47)         (48)         (46)         (48)                                   
      Angiectasis                                                   3 (6%)       3 (7%)       2 (4%)                                
      Hyperplasia                                      2 (4%)       2 (4%)       2 (4%)                                             
   Lymph Node, Mediastinal                            (34)         (38)         (37)         (37)                                   
      Hematopoietic Cell Proliferation                                           1 (3%)                                             
      Hyperplasia                                      1 (3%)       4 (11%)      2 (5%)       4 (11%)                               
   Spleen                                             (50)         (49)         (50)         (50)                                   
      Accessory Spleen                                                           1 (2%)                                             
      Angiectasis                                                                             1 (2%)                                
      Hematopoietic Cell Proliferation                26 (52%)     22 (45%)     35 (70%)     31 (62%)                               
      Hyperplasia, Lymphoid                            5 (10%)      3 (6%)                                                          
      Infiltration Cellular, Histiocyte                                                       1 (2%)                                
   Thymus                                             (34)         (28)         (25)         (34)                                   
      Hyperplasia, Lymphoid                                                                   1 (3%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (49)         (48)         (50)         (50)                                   
      Edema                                                                      2 (4%)                                             
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       1 (2%)       4 (8%)                                
      Epidermis, Hyperplasia                                                                  1 (2%)                                
      Prepuce, Inflammation, Chronic Active            4 (8%)       6 (13%)      5 (10%)      1 (2%)                                
      Subcutaneous Tissue, Cyst                                                  2 (4%)                                             
      Subcutaneous Tissue, Inflammation, Focal,                                                                                     
           Granulomatous                                                         2 (4%)                                             
      Subcutaneous Tissue, Inflammation,                                                                                            
          Suppurative                                                                         1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                           1 (2%)       1 (2%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (50)         (50)                                   
      Meninges, Inflammation, Chronic                  1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (47)         (50)         (50)                                   
      Hyperplasia                                      3 (6%)       2 (4%)       1 (2%)       4 (8%)                                
      Inflammation, Suppurative                                                               2 (4%)                                
      Epiglottis, Metaplasia, Squamous                 1 (2%)                                 1 (2%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Infiltration Cellular, Histiocyte                7 (14%)      8 (16%)     11 (22%)     22 (44%)                               
      Inflammation, Chronic, Focal                                  2 (4%)                    1 (2%)                                
      Thrombosis                                       1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia                 3 (6%)       5 (10%)      2 (4%)       2 (4%)                                
      Bronchiole, Hyperplasia                                      10 (20%)     18 (36%)     23 (46%)                               
      Mediastinum, Inflammation, Chronic                            1 (2%)                                                          
      Perivascular, Infiltration Cellular              1 (2%)                                                                       
   Nose                                               (50)         (48)         (50)         (50)                                   
      Inflammation, Suppurative                        2 (4%)       1 (2%)       4 (8%)       6 (12%)                               
      Lateral Wall, Necrosis                                                                  1 (2%)                                
      Nasolacrimal Duct, Inflammation, Suppurative                  1 (2%)                                                          
      Olfactory Epithelium, Atrophy                    7 (14%)      8 (17%)      7 (14%)     49 (98%)                               
      Olfactory Epithelium, Degeneration, Hyaline                                1 (2%)       2 (4%)                                
      Olfactory Epithelium, Hyperplasia,                                                                                            
          Adenomatous                                  3 (6%)       2 (4%)       2 (4%)      48 (96%)                               
      Olfactory Epithelium, Metaplasia                 6 (12%)      5 (10%)      5 (10%)     49 (98%)                               
      Respiratory Epithelium, Degeneration, Hyaline    3 (6%)       4 (8%)       2 (4%)      10 (20%)                               
      Respiratory Epithelium, Necrosis                                                        1 (2%)                                
      Respiratory Epithelium, Polyp, Inflammatory                   1 (2%)                                                          
   Trachea                                            (50)         (48)         (50)         (50)                                   
      Metaplasia, Squamous                             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (1)                       (1)                                    
      Inflammation                                     1 (100%)     1 (100%)                  1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (49)         (50)         (50)                                   
      Cyst                                             1 (2%)       2 (4%)       1 (2%)                                             
      Glomerulosclerosis                                                                      2 (4%)                                
      Hydronephrosis                                                1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     4 (8%)       2 (4%)       3 (6%)                                             
      Metaplasia, Osseous                              3 (6%)       1 (2%)                    1 (2%)                                
      Mineralization                                                1 (2%)                                                          
      Nephropathy                                     47 (94%)     44 (90%)     43 (86%)     42 (84%)                               
      Pigmentation, Hemosiderin                                                  1 (2%)       1 (2%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05136-08         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 10/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:54:56  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Papilla, Necrosis                                1 (2%)                                                                       
      Renal Tubule, Hyperplasia                                     4 (8%)       5 (10%)      5 (10%)                               
      Renal Tubule, Necrosis                           1 (2%)                                 1 (2%)                                
   Ureter                                             (1)                                                                           
      Transitional Epithelium, Hyperplasia             1 (100%)                                                                     
   Urinary Bladder                                    (50)         (48)         (48)         (50)                                   
      Inflammation, Suppurative                        3 (6%)       1 (2%)       3 (6%)                                             
      Transitional Epithelium, Hyperplasia             1 (2%)                    1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
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                             ----------              END OF REPORT             ----------                                           
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