National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/17665

TDMS Study 88004-06 Pathology Tables

NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09

                                                         FINAL #1 MICE




       Facility:  Battelle Northwest

       Chemical CAS #:  1321-74-0

       Lock Date:  06/17/02

       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: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                11           12            8            7                                     
    Natural Death                                      6            3            3            1                                     
    Accidently Killed                                                            1                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                33           35           38           42                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (50)         (50)         (50)                                   
      Infiltration Cellular, Mixed Cell                                                       1 (2%)                                
   Gallbladder                                        (45)         (41)         (36)         (41)                                   
      Hemorrhage, Chronic                              1 (2%)                                                                       
      Inflammation, Acute                                                        1 (3%)                                             
      Inflammation, Chronic                                                                   1 (2%)                                
   Intestine Large, Rectum                            (46)         (48)         (50)         (50)                                   
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
   Liver                                              (49)         (50)         (50)         (50)                                   
      Angiectasis                                      1 (2%)                                                                       
      Basophilic Focus                                 4 (8%)       2 (4%)                    2 (4%)                                
      Clear Cell Focus                                 4 (8%)       2 (4%)       3 (6%)                                             
      Eosinophilic Focus                              12 (24%)      8 (16%)      3 (6%)       4 (8%)                                
      Fatty Change                                     2 (4%)       1 (2%)                                                          
      Hematopoietic Cell Proliferation                              1 (2%)       1 (2%)       1 (2%)                                
      Infarct                                                       1 (2%)                                                          
      Inflammation, Acute                                                        1 (2%)                                             
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Granulomatous                      1 (2%)                    1 (2%)                                             
      Mixed Cell Focus                                                                        1 (2%)                                
      Necrosis                                         1 (2%)                    3 (6%)       1 (2%)                                
      Tension Lipidosis                                1 (2%)       5 (10%)      2 (4%)       4 (8%)                                
      Vacuolization Cytoplasmic, Focal                                                        1 (2%)                                
      Centrilobular, Hypertrophy                       1 (2%)                                                                       
   Mesentery                                          (17)         (16)         (4)          (5)                                    
      Artery, Inflammation, Chronic Active             1 (6%)                                                                       
      Fat, Congestion                                               1 (6%)                                                          
      Fat, Hemorrhage                                                            1 (25%)                                            
      Fat, Necrosis                                   17 (100%)    15 (94%)      3 (75%)      5 (100%)                              
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Pancreas                                           (48)         (50)         (50)         (50)                                   
      Atrophy                                                       2 (4%)       1 (2%)                                             
      Basophilic Focus                                                           1 (2%)                                             
      Duct, Cyst                                                                 2 (4%)                                             
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Hyperplasia, Squamous                            3 (6%)       5 (10%)                   1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)                                 2 (4%)                                
      Ulcer                                                         1 (2%)       1 (2%)                                             
   Stomach, Glandular                                 (49)         (50)         (49)         (49)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Necrosis                                         1 (2%)                                                                       
   Tooth                                              (9)          (13)         (8)          (15)                                   
      Incisor, Dysplasia                               9 (100%)    13 (100%)     8 (100%)    15 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (1)                                                                           
      Aorta, Mineralization                            1 (100%)                                                                     
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   3 (6%)       6 (12%)      1 (2%)       1 (2%)                                
      Infiltration Cellular, Polymorphonuclear                                   1 (2%)                                             
      Inflammation, Suppurative                                     1 (2%)                                                          
      Mineralization                                   1 (2%)       1 (2%)                    1 (2%)                                
      Necrosis                                                                   1 (2%)                                             
      Thrombosis                                                    1 (2%)                                                          
      Artery, Inflammation, Chronic Active             2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Hematopoietic Cell Proliferation                              1 (2%)                                                          
      Hyperplasia                                      1 (2%)       2 (4%)       5 (10%)      4 (8%)                                
      Hypertrophy                                                   3 (6%)       2 (4%)       8 (16%)                               
   Adrenal Medulla                                    (49)         (50)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)       1 (2%)                    2 (4%)                                
      Necrosis                                         1 (2%)                                                                       
   Islets, Pancreatic                                 (48)         (49)         (49)         (50)                                   
      Hyperplasia                                                                1 (2%)                                             
   Pituitary Gland                                    (47)         (50)         (49)         (45)                                   
      Cyst                                                                                    1 (2%)                                
      Pars Distalis, Angiectasis                       3 (6%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Distalis, Hyperplasia                       8 (17%)     16 (32%)      6 (12%)      5 (11%)                               
   Thyroid Gland                                      (49)         (49)         (50)         (48)                                   
      C-Cell, Hyperplasia                                           1 (2%)                                                          
      Follicular Cell, Hyperplasia                     1 (2%)       2 (4%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (48)         (50)         (49)         (49)                                   
      Angiectasis                                      2 (4%)       3 (6%)                                                          
      Cyst                                             9 (19%)     14 (28%)     10 (20%)      9 (18%)                               
      Inflammation, Acute                                                        1 (2%)                                             
      Mineralization                                   1 (2%)                                                                       
      Necrosis                                                                   1 (2%)                                             
      Thrombosis                                                                              1 (2%)                                
   Uterus                                             (49)         (50)         (50)         (49)                                   
      Angiectasis                                                   1 (2%)       2 (4%)       1 (2%)                                
      Endometrium, Hyperplasia, Cystic                 2 (4%)       8 (16%)      5 (10%)      8 (16%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Lymph Node                                         (9)          (3)          (5)          (2)                                    
      Ectasia                                          1 (11%)                                                                      
      Deep Cervical, Hyperplasia, Lymphoid             1 (11%)                                                                      
      Deep Cervical, Infiltration Cellular, Plasma                                                                                  
        Cell                                                                                  1 (50%)                               
      Iliac, Angiectasis                                                                      1 (50%)                               
      Iliac, Ectasia                                   1 (11%)                                                                      
      Lumbar, Angiectasis                                                        1 (20%)                                            
      Renal, Angiectasis                                                         1 (20%)                                            
   Lymph Node, Mesenteric                             (49)         (50)         (49)         (49)                                   
      Angiectasis                                      1 (2%)                                                                       
      Ectasia                                                                    1 (2%)                                             
      Inflammation, Granulomatous                                   1 (2%)                                                          
   Spleen                                             (49)         (50)         (49)         (49)                                   
      Hematopoietic Cell Proliferation                 3 (6%)       3 (6%)       3 (6%)       1 (2%)                                
      Inflammation, Acute                                                        1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Necrosis                                                                   1 (2%)                                             
      Sinusoid, Dilatation                                                                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     3 (6%)       2 (4%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Degeneration, Focal                                                                     1 (2%)                                
      Hemorrhage                                                    1 (2%)                                                          
      Meninges, Infiltration Cellular, Mononuclear                                                                                  
        Cell                                           1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (48)         (50)         (50)         (49)                                   
      Hyperplasia, Squamous                                                                   1 (2%)                                
      Inflammation, Suppurative                                     1 (2%)                    1 (2%)                                
   Lung                                               (50)         (50)         (50)         (49)                                   
      Hemorrhage                                       1 (2%)                                                                       
      Infiltration Cellular, Polymorphonuclear                                   1 (2%)                                             
      Inflammation, Acute                                                        1 (2%)                                             
      Thrombosis                                                                 1 (2%)                                             
      Alveolar Epithelium, Hyperplasia                 4 (8%)       3 (6%)       4 (8%)       8 (16%)                               
      Alveolus, Granuloma                                                        1 (2%)                                             
      Alveolus, Infiltration Cellular, Histiocyte      3 (6%)       6 (12%)      9 (18%)     17 (35%)                               
      Bronchiole, Hyperplasia                                                                 1 (2%)                                
      Bronchiole, Hyperplasia, Atypical                            39 (78%)     45 (90%)     48 (98%)                               
   Nose                                               (50)         (50)         (50)         (49)                                   
      Inflammation, Suppurative                        1 (2%)      50 (100%)    49 (98%)     49 (100%)                              
      Glands, Respiratory Epithelium, Metaplasia       3 (6%)      50 (100%)    50 (100%)    49 (100%)                              
      Olfactory Epithelium, Atrophy                    8 (16%)                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Olfactory Epithelium, Degeneration, Hyaline      2 (4%)      50 (100%)    40 (80%)      8 (16%)                               
      Olfactory Epithelium, Respiratory Epithelium,                                                                                 
         Metaplasia                                                50 (100%)    50 (100%)    49 (100%)                              
   Trachea                                            (49)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (49)                                   
      Cataract                                         1 (2%)       2 (4%)                    1 (2%)                                
      Inflammation                                                                            1 (2%)                                
      Phthisis Bulbi                                   1 (2%)       1 (2%)                                                          
      Cornea, Hyperplasia, Squamous                                              1 (2%)                                             
      Cornea, Inflammation, Chronic Active             1 (2%)       3 (6%)                    3 (6%)                                
      Cornea, Inflammation, Suppurative                                                       1 (2%)                                
      Cornea, Mineralization                                                                  6 (12%)                               
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       4 (8%)       2 (4%)       3 (6%)                                
      Inflammation, Chronic Active                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Amyloid Deposition                                            1 (2%)                                                          
      Infarct                                                                    1 (2%)                                             
      Inflammation, Suppurative                                     2 (4%)       2 (4%)                                             
      Metaplasia, Osseous                              2 (4%)       3 (6%)       3 (6%)       1 (2%)                                
      Mineralization                                   1 (2%)                                                                       
      Nephropathy                                     25 (51%)     31 (62%)     22 (44%)     17 (34%)                               
      Artery, Inflammation, Chronic Active                                                    1 (2%)                                
   Urinary Bladder                                    (49)         (50)         (50)         (49)                                   
      Inflammation, Suppurative                                                  1 (2%)                                             
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 7            6            5            4                                     
    Natural Death                                      2            6            3            3                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                41           38           42           43                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Basophilic Focus                                 3 (6%)       6 (12%)      7 (14%)      4 (8%)                                
      Clear Cell Focus                                 9 (18%)     11 (22%)      6 (12%)      5 (10%)                               
      Eosinophilic Focus                               8 (16%)      7 (14%)                   2 (4%)                                
      Fatty Change                                                  2 (4%)       1 (2%)                                             
      Infarct                                          2 (4%)                    1 (2%)                                             
      Inflammation, Granulomatous                      1 (2%)                                                                       
      Mineralization                                   1 (2%)                                                                       
      Mixed Cell Focus                                 2 (4%)       1 (2%)       2 (4%)       1 (2%)                                
      Necrosis                                         1 (2%)       2 (4%)       2 (4%)       2 (4%)                                
      Tension Lipidosis                                2 (4%)       1 (2%)       2 (4%)       1 (2%)                                
      Vacuolization Cytoplasmic, Focal                 2 (4%)                                                                       
   Mesentery                                          (11)         (4)          (4)          (5)                                    
      Fat, Necrosis                                   10 (91%)      4 (100%)     4 (100%)     5 (100%)                              
   Pancreas                                           (49)         (48)         (50)         (50)                                   
      Duct, Cyst                                       2 (4%)                                                                       
   Stomach, Forestomach                               (49)         (50)         (49)         (50)                                   
      Hyperplasia, Squamous                            1 (2%)       4 (8%)       2 (4%)       4 (8%)                                
      Inflammation                                                  1 (2%)                                                          
      Inflammation, Acute                                           2 (4%)                    1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       1 (2%)                    3 (6%)                                
      Mineralization                                                                          1 (2%)                                
      Ulcer                                                         2 (4%)       1 (2%)       1 (2%)                                
   Stomach, Glandular                                 (48)         (48)         (47)         (49)                                   
      Inflammation, Acute                                           1 (2%)                                                          
      Mineralization                                                1 (2%)                                                          
      Necrosis                                                      1 (2%)                    1 (2%)                                
   Tooth                                              (41)         (43)         (41)         (35)                                   
      Incisor, Dysplasia                              41 (100%)    43 (100%)    41 (100%)    35 (100%)                              
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                  14 (28%)      5 (10%)      5 (10%)      5 (10%)                               
      Mineralization                                   1 (2%)       1 (2%)                    1 (2%)                                
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (49)         (50)         (50)                                   
      Hyperplasia                                      9 (18%)     10 (20%)      6 (12%)      5 (10%)                               
      Hypertrophy                                     24 (49%)     25 (51%)     26 (52%)     24 (48%)                               
   Adrenal Medulla                                    (49)         (49)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       2 (4%)                    2 (4%)                                
   Parathyroid Gland                                  (35)         (39)         (36)         (35)                                   
      Hyperplasia                                                                1 (3%)                                             
   Pituitary Gland                                    (48)         (47)         (47)         (46)                                   
      Cyst                                                          1 (2%)                                                          
      Pars Distalis, Hyperplasia                       2 (4%)       1 (2%)       2 (4%)       1 (2%)                                
   Thyroid Gland                                      (49)         (49)         (50)         (50)                                   
      Follicular Cell, Hyperplasia                                  2 (4%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  1 (2%)       2 (4%)                                                          
   Penis                                                                        (1)                                                 
      Inflammation, Acute                                                        1 (100%)                                           
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Ectasia                                          1 (2%)       3 (6%)       2 (4%)       1 (2%)                                
      Inflammation, Chronic Active                                               2 (4%)                                             
   Seminal Vesicle                                    (49)         (48)         (50)         (49)                                   
      Inflammation, Chronic                                         1 (2%)                                                          
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          2 (4%)                                                                       
      Mineralization                                   1 (2%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Interstitial Cell, Hyperplasia                                             1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (48)         (50)         (50)                                   
      Necrosis                                         1 (2%)                                                                       
   Spleen                                             (49)         (48)         (50)         (50)                                   
      Hematopoietic Cell Proliferation                 1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 (2%)                                                                       
      Inflammation, Chronic Active                     3 (6%)       1 (2%)                    2 (4%)                                
      Inflammation, Granulomatous                                                             1 (2%)                                
      Subcutaneous Tissue, Cyst Epithelial                                                                                          
        Inclusion                                                   1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Necrosis, Focal                                  1 (2%)                                                                       
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                        1 (2%)                                                                       
   Lung                                               (49)         (49)         (49)         (49)                                   
      Hemorrhage                                       1 (2%)                                 1 (2%)                                
      Mineralization                                                1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia                 1 (2%)       5 (10%)      5 (10%)      7 (14%)                               
      Alveolus, Infiltration Cellular, Histiocyte      2 (4%)       4 (8%)       5 (10%)      1 (2%)                                
      Bronchiole, Hyperplasia                                                    1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                           DIVINYLBENZENE                                      Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:01:09    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      10 PPM       30 PPM       100 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Bronchiole, Hyperplasia, Atypical                            38 (78%)     46 (94%)     46 (94%)                               
      Bronchiole, Inflammation, Chronic Active                                                1 (2%)                                
   Nose                                               (50)         (50)         (49)         (50)                                   
      Inflammation, Suppurative                        3 (6%)      47 (94%)     49 (100%)    49 (98%)                               
      Glands, Necrosis                                              1 (2%)                                                          
      Glands, Respiratory Epithelium, Metaplasia      12 (24%)     50 (100%)    49 (100%)    50 (100%)                              
      Olfactory Epithelium, Atrophy                   14 (28%)                                                                      
      Olfactory Epithelium, Degeneration, Hyaline      5 (10%)     50 (100%)    48 (98%)     11 (22%)                               
      Olfactory Epithelium, Respiratory Epithelium,                                                                                 
         Metaplasia                                    1 (2%)      50 (100%)    49 (100%)    50 (100%)                              
      Respiratory Epithelium, Metaplasia, Squamous                                            1 (2%)                                
      Sinus, Foreign Body                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (49)         (47)         (47)         (50)                                   
      Phthisis Bulbi                                                             1 (2%)       1 (2%)                                
      Cornea, Inflammation, Chronic Active                          2 (4%)       1 (2%)       1 (2%)                                
      Cornea, Mineralization                                                                  2 (4%)                                
   Harderian Gland                                    (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      2 (4%)       2 (4%)       3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             1 (2%)                    2 (4%)                                             
      Infarct                                          1 (2%)       2 (4%)       1 (2%)                                             
      Inflammation, Suppurative                        1 (2%)                                                                       
      Metaplasia, Osseous                              7 (14%)      3 (6%)       5 (10%)      1 (2%)                                
      Nephropathy                                     45 (90%)     43 (86%)     40 (80%)     34 (68%)                               
      Capsule, Fibrosis                                1 (2%)                                                                       
      Papilla, Necrosis                                1 (2%)                                                                       
      Pelvis, Dilatation                                            1 (2%)                                                          
      Renal Tubule, Hyperplasia                        2 (4%)       1 (2%)                                                          
      Renal Tubule, Necrosis                                                                  1 (2%)                                
   Urinary Bladder                                    (48)         (48)         (49)         (49)                                   
      Transitional Epithelium, Hyperplasia             1 (2%)                                                                       
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------                                           
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.