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TDMS Study 88004-06 Pathology Tables

NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26

                                                         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
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)

                                                              Page   1


NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         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 [3.0]                               
   Gallbladder                                        (45)         (41)         (36)         (41)                                   
      Hemorrhage, Chronic                              1 [3.0]                                                                      
      Inflammation, Acute                                                        1 [3.0]                                            
      Inflammation, Chronic                                                                   1 [2.0]                               
   Intestine Large, Rectum                            (46)         (48)         (50)         (50)                                   
      Artery, Inflammation, Chronic Active             1 [3.0]                                                                      
   Liver                                              (49)         (50)         (50)         (50)                                   
      Angiectasis                                      1 [1.0]                                                                      
      Basophilic Focus                                 4            2                         2                                     
      Clear Cell Focus                                 4            2            3                                                  
      Eosinophilic Focus                              12            8            3            4                                     
      Fatty Change                                     2 [2.0]      1 [2.0]                                                         
      Hematopoietic Cell Proliferation                              1 [4.0]      1 [3.0]      1 [2.0]                               
      Infarct                                                       1                                                               
      Inflammation, Acute                                                        1 [3.0]                                            
      Inflammation, Chronic                                                                   1 [2.0]                               
      Inflammation, Granulomatous                      1 [3.0]                   1 [1.0]                                            
      Mixed Cell Focus                                                                        1                                     
      Necrosis                                         1 [2.0]                   3 [2.0]      1 [3.0]                               
      Tension Lipidosis                                1 [2.0]      5 [1.4]      2 [1.5]      4 [1.5]                               
      Vacuolization Cytoplasmic, Focal                                                        1 [3.0]                               
      Centrilobular, Hypertrophy                       1 [3.0]                                                                      
   Mesentery                                          (17)         (16)         (4)          (5)                                    
      Artery, Inflammation, Chronic Active             1 [2.0]                                                                      
      Fat, Congestion                                               1 [2.0]                                                         
      Fat, Hemorrhage                                                            1 [2.0]                                            
      Fat, Necrosis                                   17 [2.0]     15 [2.0]      3 [2.0]      5 [2.0]                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Pancreas                                           (48)         (50)         (50)         (50)                                   
      Atrophy                                                       2 [4.0]      1 [4.0]                                            
      Basophilic Focus                                                           1 [2.0]                                            
      Duct, Cyst                                                                 2 [4.0]                                            
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Hyperplasia, Squamous                            3 [1.7]      5 [2.2]                   1 [2.0]                               
      Inflammation, Chronic Active                     1 [1.0]                                2 [2.0]                               
      Ulcer                                                         1 [2.0]      1 [1.0]                                            
   Stomach, Glandular                                 (49)         (50)         (49)         (49)                                   
      Hemorrhage                                                    1 [2.0]                                                         
      Necrosis                                         1 [2.0]                                                                      
   Tooth                                              (9)          (13)         (8)          (15)                                   
      Incisor, Dysplasia                               9 [1.7]     13 [1.7]      8 [1.5]     15 [1.7]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (1)                                                                           
      Aorta, Mineralization                            1 [2.0]                                                                      
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   3 [1.0]      6 [1.0]      1 [1.0]      1 [1.0]                               
      Infiltration Cellular, Polymorphonuclear                                   1 [2.0]                                            
      Inflammation, Suppurative                                     1 [2.0]                                                         
      Mineralization                                   1 [1.0]      1 [2.0]                   1 [1.0]                               
      Necrosis                                                                   1 [2.0]                                            
      Thrombosis                                                    1 [3.0]                                                         
      Artery, Inflammation, Chronic Active             2 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Hematopoietic Cell Proliferation                              1 [3.0]                                                         
      Hyperplasia                                      1 [3.0]      2 [2.0]      5 [2.2]      4 [2.0]                               
      Hypertrophy                                                   3 [2.0]      2 [1.0]      8 [2.0]                               
   Adrenal Medulla                                    (49)         (50)         (49)         (50)                                   
      Hyperplasia                                      1 [2.0]      1 [2.0]                   2 [2.0]                               
      Necrosis                                         1 [2.0]                                                                      
   Islets, Pancreatic                                 (48)         (49)         (49)         (50)                                   
      Hyperplasia                                                                1 [3.0]                                            
   Pituitary Gland                                    (47)         (50)         (49)         (45)                                   
      Cyst                                                                                    1 [2.0]                               
      Pars Distalis, Angiectasis                       3 [2.0]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Distalis, Hyperplasia                       8 [2.4]     16 [2.1]      6 [1.7]      5 [2.2]                               
   Thyroid Gland                                      (49)         (49)         (50)         (48)                                   
      C-Cell, Hyperplasia                                           1 [1.0]                                                         
      Follicular Cell, Hyperplasia                     1 [2.0]      2 [3.0]                   1 [1.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (48)         (50)         (49)         (49)                                   
      Angiectasis                                      2 [2.5]      3 [2.7]                                                         
      Cyst                                             9 [2.1]     14 [2.5]     10 [2.6]      9 [2.2]                               
      Inflammation, Acute                                                        1 [4.0]                                            
      Mineralization                                   1 [2.0]                                                                      
      Necrosis                                                                   1 [4.0]                                            
      Thrombosis                                                                              1 [3.0]                               
   Uterus                                             (49)         (50)         (50)         (49)                                   
      Angiectasis                                                   1 [3.0]      2 [3.0]      1 [4.0]                               
      Endometrium, Hyperplasia, Cystic                 2 [3.0]      8 [3.8]      5 [2.8]      8 [3.3]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Lymph Node                                         (9)          (3)          (5)          (2)                                    
      Ectasia                                          1 [3.0]                                                                      
      Deep Cervical, Hyperplasia, Lymphoid             1 [4.0]                                                                      
      Deep Cervical, Infiltration Cellular, Plasma                                                                                  
        Cell                                                                                  1 [3.0]                               
      Iliac, Angiectasis                                                                      1 [3.0]                               
      Iliac, Ectasia                                   1 [3.0]                                                                      
      Lumbar, Angiectasis                                                        1 [3.0]                                            
      Renal, Angiectasis                                                         1 [3.0]                                            
   Lymph Node, Mesenteric                             (49)         (50)         (49)         (49)                                   
      Angiectasis                                      1 [3.0]                                                                      
      Ectasia                                                                    1 [3.0]                                            
      Inflammation, Granulomatous                                   1 [2.0]                                                         
   Spleen                                             (49)         (50)         (49)         (49)                                   
      Hematopoietic Cell Proliferation                 3 [2.7]      3 [3.0]      3 [2.7]      1 [3.0]                               
      Inflammation, Acute                                                        1 [3.0]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Necrosis                                                                   1 [3.0]                                            
      Sinusoid, Dilatation                                                                    1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     3 [1.7]      2 [3.5]                   1 [4.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Degeneration, Focal                                                                     1 [2.0]                               
      Hemorrhage                                                    1 [2.0]                                                         
      Meninges, Infiltration Cellular, Mononuclear                                                                                  
        Cell                                           1 [1.0]      1 [2.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (48)         (50)         (50)         (49)                                   
      Hyperplasia, Squamous                                                                   1 [2.0]                               
      Inflammation, Suppurative                                     1 [2.0]                   1 [1.0]                               
   Lung                                               (50)         (50)         (50)         (49)                                   
      Hemorrhage                                       1 [1.0]                                                                      
      Infiltration Cellular, Polymorphonuclear                                   1 [2.0]                                            
      Inflammation, Acute                                                        1 [2.0]                                            
      Thrombosis                                                                 1 [2.0]                                            
      Alveolar Epithelium, Hyperplasia                 4 [1.8]      3 [1.7]      4 [2.3]      8 [2.5]                               
      Alveolus, Granuloma                                                        1 [1.0]                                            
      Alveolus, Infiltration Cellular, Histiocyte      3 [1.0]      6 [1.0]      9 [1.1]     17 [1.2]                               
      Bronchiole, Hyperplasia                                                                 1 [4.0]                               
      Bronchiole, Hyperplasia, Atypical                            39 [1.3]     45 [1.8]     48 [2.1]                               
   Nose                                               (50)         (50)         (50)         (49)                                   
      Inflammation, Suppurative                        1 [1.0]     50 [1.7]     49 [2.0]     49 [2.4]                               
      Glands, Respiratory Epithelium, Metaplasia       3 [1.0]     50 [3.1]     50 [3.6]     49 [4.0]                               
      Olfactory Epithelium, Atrophy                    8 [1.1]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Olfactory Epithelium, Degeneration, Hyaline      2 [1.5]     50 [2.4]     40 [1.8]      8 [1.6]                               
      Olfactory Epithelium, Respiratory Epithelium,                                                                                 
         Metaplasia                                                50 [3.1]     50 [3.9]     49 [3.9]                               
   Trachea                                            (49)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                     1 [2.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (49)                                   
      Cataract                                         1 [3.0]      2 [2.5]                   1 [2.0]                               
      Inflammation                                                                            1 [2.0]                               
      Phthisis Bulbi                                   1 [4.0]      1 [3.0]                                                         
      Cornea, Hyperplasia, Squamous                                              1 [2.0]                                            
      Cornea, Inflammation, Chronic Active             1 [2.0]      3 [2.3]                   3 [3.0]                               
      Cornea, Inflammation, Suppurative                                                       1 [3.0]                               
      Cornea, Mineralization                                                                  6 [1.0]                               
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 [3.0]      4 [2.5]      2 [2.0]      3 [2.3]                               
      Inflammation, Chronic Active                     1 [4.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Amyloid Deposition                                            1 [3.0]                                                         
      Infarct                                                                    1 [4.0]                                            
      Inflammation, Suppurative                                     2 [2.5]      2 [3.5]                                            
      Metaplasia, Osseous                              2 [1.5]      3 [1.3]      3 [1.0]      1 [1.0]                               
      Mineralization                                   1 [1.0]                                                                      
      Nephropathy                                     25 [1.3]     31 [1.3]     22 [1.2]     17 [1.1]                               
      Artery, Inflammation, Chronic Active                                                    1 [2.0]                               
   Urinary Bladder                                    (49)         (50)         (50)         (49)                                   
      Inflammation, Suppurative                                                  1 [2.0]                                            
      Artery, Inflammation, Chronic Active             1 [2.0]                                                                      
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         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 [1.0]                               
      Basophilic Focus                                 3            6            7            4                                     
      Clear Cell Focus                                 9           11            6            5                                     
      Eosinophilic Focus                               8            7                         2                                     
      Fatty Change                                                  2 [1.5]      1 [2.0]                                            
      Infarct                                          2                         1                                                  
      Inflammation, Granulomatous                      1 [1.0]                                                                      
      Mineralization                                   1 [1.0]                                                                      
      Mixed Cell Focus                                 2            1            2            1                                     
      Necrosis                                         1 [1.0]      2 [1.5]      2 [3.0]      2 [3.0]                               
      Tension Lipidosis                                2 [2.0]      1 [2.0]      2 [1.5]      1 [2.0]                               
      Vacuolization Cytoplasmic, Focal                 2 [2.5]                                                                      
   Mesentery                                          (11)         (4)          (4)          (5)                                    
      Fat, Necrosis                                   10 [2.0]      4 [2.0]      4 [2.0]      5 [2.0]                               
   Pancreas                                           (49)         (48)         (50)         (50)                                   
      Duct, Cyst                                       2 [3.5]                                                                      
   Stomach, Forestomach                               (49)         (50)         (49)         (50)                                   
      Hyperplasia, Squamous                            1 [2.0]      4 [2.5]      2 [1.0]      4 [2.3]                               
      Inflammation                                                  1 [2.0]                                                         
      Inflammation, Acute                                           2 [1.5]                   1 [1.0]                               
      Inflammation, Chronic Active                     1 [2.0]      1 [2.0]                   3 [2.3]                               
      Mineralization                                                                          1 [1.0]                               
      Ulcer                                                         2 [2.5]      1 [2.0]      1 [3.0]                               
   Stomach, Glandular                                 (48)         (48)         (47)         (49)                                   
      Inflammation, Acute                                           1 [1.0]                                                         
      Mineralization                                                1 [2.0]                                                         
      Necrosis                                                      1 [2.0]                   1 [1.0]                               
   Tooth                                              (41)         (43)         (41)         (35)                                   
      Incisor, Dysplasia                              41 [2.2]     43 [2.6]     41 [2.5]     35 [2.3]                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                  14 [1.1]      5 [1.0]      5 [1.0]      5 [1.0]                               
      Mineralization                                   1 [1.0]      1 [1.0]                   1 [1.0]                               
      Artery, Inflammation, Chronic Active             1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (49)         (50)         (50)                                   
      Hyperplasia                                      9 [2.0]     10 [1.9]      6 [1.7]      5 [2.0]                               
      Hypertrophy                                     24 [2.0]     25 [1.9]     26 [2.0]     24 [1.6]                               
   Adrenal Medulla                                    (49)         (49)         (50)         (50)                                   
      Hyperplasia                                      1 [2.0]      2 [2.0]                   2 [2.5]                               
   Parathyroid Gland                                  (35)         (39)         (36)         (35)                                   
      Hyperplasia                                                                1 [3.0]                                            
   Pituitary Gland                                    (48)         (47)         (47)         (46)                                   
      Cyst                                                          1 [3.0]                                                         
      Pars Distalis, Hyperplasia                       2 [2.5]      1 [2.0]      2 [1.5]      1 [1.0]                               
   Thyroid Gland                                      (49)         (49)         (50)         (50)                                   
      Follicular Cell, Hyperplasia                                  2 [1.5]      1 [3.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  1 [2.0]      2 [1.5]                                                         
   Penis                                                                        (1)                                                 
      Inflammation, Acute                                                        1 [4.0]                                            
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Ectasia                                          1 [2.0]      3 [2.3]      2 [3.0]      1 [3.0]                               
      Inflammation, Chronic Active                                               2 [3.0]                                            
   Seminal Vesicle                                    (49)         (48)         (50)         (49)                                   
      Inflammation, Chronic                                         1 [3.0]                                                         
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          2 [3.0]                                                                      
      Mineralization                                   1 [4.0]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Interstitial Cell, Hyperplasia                                             1 [2.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (48)         (50)         (50)                                   
      Necrosis                                         1 [4.0]                                                                      
   Spleen                                             (49)         (48)         (50)         (50)                                   
      Hematopoietic Cell Proliferation                 1 [3.0]                   1 [2.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 [3.0]                                                                      
      Inflammation, Chronic Active                     3 [2.0]      1 [1.0]                   2 [3.5]                               
      Inflammation, Granulomatous                                                             1 [2.0]                               
      Subcutaneous Tissue, Cyst Epithelial                                                                                          
        Inclusion                                                   1                                                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Necrosis, Focal                                  1 [2.0]                                                                      
      Artery, Inflammation, Chronic Active             1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                        1 [3.0]                                                                      
   Lung                                               (49)         (49)         (49)         (49)                                   
      Hemorrhage                                       1 [2.0]                                1 [4.0]                               
      Mineralization                                                1 [2.0]                                                         
      Alveolar Epithelium, Hyperplasia                 1 [1.0]      5 [3.2]      5 [2.0]      7 [2.0]                               
      Alveolus, Infiltration Cellular, Histiocyte      2 [1.5]      4 [1.0]      5 [1.0]      1 [1.0]                               
      Bronchiole, Hyperplasia                                                    1 [1.0]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 88004-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/14/03    
Route: RESPIRATORY EXPOSURE WHOLE BODY                          DIVINYLBENZENE                                    Time: 13:13:26    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             CONTROL      10 PPM       30 PPM       100 PPM                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Bronchiole, Hyperplasia, Atypical                            38 [1.1]     46 [1.8]     46 [1.9]                               
      Bronchiole, Inflammation, Chronic Active                                                1 [3.0]                               
   Nose                                               (50)         (50)         (49)         (50)                                   
      Inflammation, Suppurative                        3 [1.0]     47 [1.4]     49 [1.9]     49 [1.9]                               
      Glands, Necrosis                                              1 [2.0]                                                         
      Glands, Respiratory Epithelium, Metaplasia      12 [1.0]     50 [2.9]     49 [4.0]     50 [3.9]                               
      Olfactory Epithelium, Atrophy                   14 [1.1]                                                                      
      Olfactory Epithelium, Degeneration, Hyaline      5 [1.0]     50 [1.9]     48 [1.8]     11 [1.1]                               
      Olfactory Epithelium, Respiratory Epithelium,                                                                                 
         Metaplasia                                    1 [2.0]     50 [3.1]     49 [4.0]     50 [3.9]                               
      Respiratory Epithelium, Metaplasia, Squamous                                            1 [2.0]                               
      Sinus, Foreign Body                                                        1                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (49)         (47)         (47)         (50)                                   
      Phthisis Bulbi                                                             1 [4.0]      1 [3.0]                               
      Cornea, Inflammation, Chronic Active                          2 [2.0]      1 [3.0]      1 [2.0]                               
      Cornea, Mineralization                                                                  2 [1.0]                               
   Harderian Gland                                    (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      2 [2.0]      2 [2.0]      3 [2.7]      2 [1.5]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             1 [2.0]                   2 [2.0]                                            
      Infarct                                          1 [3.0]      2 [2.5]      1 [2.0]                                            
      Inflammation, Suppurative                        1 [2.0]                                                                      
      Metaplasia, Osseous                              7 [1.0]      3 [1.0]      5 [1.0]      1 [1.0]                               
      Nephropathy                                     45 [1.6]     43 [1.5]     40 [1.3]     34 [1.3]                               
      Capsule, Fibrosis                                1 [1.0]                                                                      
      Papilla, Necrosis                                1 [2.0]                                                                      
      Pelvis, Dilatation                                            1 [2.0]                                                         
      Renal Tubule, Hyperplasia                        2 [1.0]      1 [1.0]                                                         
      Renal Tubule, Necrosis                                                                  1 [2.0]                               
   Urinary Bladder                                    (48)         (48)         (49)         (49)                                   
      Transitional Epithelium, Hyperplasia             1 [3.0]                                                                      
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
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