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TDMS Study 05200-06 Pathology Tables

NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51




       Facility:  Battelle Northwest

       Chemical CAS #:  75-52-5

       Lock Date:  06/22/92

       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: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      7            5            3            2                                     
    Moribund Sacrifice                                16           17           20           12                                     
    Accidently Killed                                  2                         1                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                25           27           26           36                                     
    Moribund Sacrifice                                              1                                                               

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (48)         (48)         (49)         (49)                                   
      Epithelium, Hyperplasia                          1 (2%)                                 1 (2%)                                
   Gallbladder                                        (40)         (45)         (45)         (46)                                   
      Inflammation, Chronic                                         1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)       1 (2%)                                             
   Intestine Large, Cecum                             (49)         (46)         (47)         (50)                                   
      Diverticulum                                                                            1 (2%)                                
      Muscularis, Hyperplasia                          1 (2%)                                                                       
   Intestine Small, Duodenum                          (48)         (43)         (45)         (49)                                   
      Cyst                                             1 (2%)                                                                       
      Peyer's Patch, Hyperplasia                                    1 (2%)                                                          
   Intestine Small, Jejunum                           (47)         (45)         (47)         (48)                                   
      Epithelium, Hyperplasia                                                                 1 (2%)                                
   Liver                                              (50)         (49)         (49)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Basophilic Focus                                 1 (2%)                                 1 (2%)                                
      Eosinophilic Focus                               4 (8%)       7 (14%)     11 (22%)     15 (30%)                               
      Hematopoietic Cell Proliferation                 2 (4%)       4 (8%)       2 (4%)       2 (4%)                                
      Inflammation, Chronic                            1 (2%)       3 (6%)                    1 (2%)                                
      Mixed Cell Focus                                              2 (4%)       1 (2%)       1 (2%)                                
      Necrosis                                         2 (4%)       2 (4%)       3 (6%)                                             
      Vacuolization Cytoplasmic                                                               1 (2%)                                
      Bile Duct, Cyst                                               1 (2%)                                                          
      Centrilobular, Degeneration, Fatty               1 (2%)       1 (2%)                                                          
      Centrilobular, Necrosis                          1 (2%)       3 (6%)                                                          
   Mesentery                                          (7)          (14)         (8)          (11)                                   
      Hemorrhage                                                    1 (7%)                                                          
      Inflammation, Suppurative                                                  1 (13%)                                            
      Fat, Hemorrhage                                                            1 (13%)                                            
      Fat, Necrosis                                    6 (86%)     11 (79%)      5 (63%)     10 (91%)                               
      Fat, Thrombosis                                               1 (7%)                                                          
   Pancreas                                           (50)         (48)         (48)         (50)                                   

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

                                                             Page    2                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Atrophy                                          2 (4%)       2 (4%)       1 (2%)       2 (4%)                                
      Basophilic Focus                                 2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
      Necrosis                                                                                1 (2%)                                
      Duct, Cyst                                                                 1 (2%)       2 (4%)                                
      Duct, Inflammation, Suppurative                                                         1 (2%)                                
   Salivary Glands                                    (49)         (48)         (49)         (50)                                   
      Atrophy                                                                    1 (2%)                                             
   Stomach, Forestomach                               (50)         (48)         (49)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Inflammation, Suppurative                        1 (2%)       1 (2%)                                                          
      Ulcer                                            3 (6%)                                 1 (2%)                                
      Epithelium, Hyperplasia                          1 (2%)       4 (8%)       3 (6%)       1 (2%)                                
   Stomach, Glandular                                 (49)         (48)         (48)         (50)                                   
      Degeneration, Hyaline                                                                   1 (2%)                                
      Inflammation                                                  1 (2%)       1 (2%)                                             
      Ulcer                                            1 (2%)                    1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                    (1)          (2)                                                 
      Aorta, Mineralization                                         1 (100%)     1 (50%)                                            
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  13 (26%)     23 (46%)     19 (38%)     18 (36%)                               
      Mineralization                                   1 (2%)                                                                       
      Thrombosis                                                                              1 (2%)                                
      Artery, Inflammation                             1 (2%)                                                                       
      Endothelium, Hyperplasia                         1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (48)         (49)         (50)                                   
      Degeneration, Cystic                             1 (2%)                                 3 (6%)                                
      Hyperplasia                                                   1 (2%)                    2 (4%)                                
      Hypertrophy                                      2 (4%)       4 (8%)       5 (10%)      3 (6%)                                
      Capsule, Hyperplasia                                          2 (4%)                    2 (4%)                                
   Adrenal Medulla                                    (50)         (48)         (49)         (49)                                   
      Hyperplasia                                      1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
   Islets, Pancreatic                                 (50)         (48)         (47)         (50)                                   
      Hyperplasia                                                                1 (2%)       1 (2%)                                
   Parathyroid Gland                                  (33)         (34)         (33)         (34)                                   
      Cyst                                                          1 (3%)                                                          
   Pituitary Gland                                    (50)         (46)         (48)         (50)                                   
      Pars Distalis, Angiectasis                                    1 (2%)                                                          
      Pars Distalis, Hyperplasia                      11 (22%)     20 (43%)     11 (23%)     18 (36%)                               
      Pars Intermedia, Hyperplasia                     1 (2%)                                                                       

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

                                                             Page    3                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Intermedia, Hypertrophy                                  1 (2%)                                                          
   Thyroid Gland                                      (50)         (48)         (48)         (50)                                   
      Follicular Cell, Hyperplasia                     5 (10%)      4 (8%)       3 (6%)       5 (10%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (47)         (47)         (48)         (48)                                   
      Angiectasis                                      4 (9%)       2 (4%)       1 (2%)                                             
      Atrophy                                         14 (30%)     16 (34%)     14 (29%)     13 (27%)                               
      Cyst                                            13 (28%)     14 (30%)     16 (33%)     13 (27%)                               
      Hyperplasia, Tubular                             3 (6%)       2 (4%)       2 (4%)                                             
      Thrombosis                                       1 (2%)                                 1 (2%)                                
      Bilateral, Cyst                                               1 (2%)                                                          
      Granulosa Cell, Hyperplasia                                   1 (2%)                                                          
      Interstitial Cell, Hyperplasia                                             1 (2%)                                             
   Uterus                                             (50)         (49)         (49)         (50)                                   
      Adenomyosis                                                                1 (2%)                                             
      Angiectasis                                      2 (4%)       2 (4%)       4 (8%)                                             
      Hemorrhage                                                                 1 (2%)                                             
      Hydrometra                                       3 (6%)       4 (8%)       5 (10%)     10 (20%)                               
      Hyperplasia, Cystic                              4 (8%)       6 (12%)      3 (6%)       2 (4%)                                
      Inflammation, Suppurative                                                               1 (2%)                                
      Thrombosis                                                    1 (2%)       2 (4%)                                             
      Myometrium, Hyperplasia                                                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (48)         (49)         (50)                                   
      Hyperplasia                                                   3 (6%)                                                          
      Infiltration Cellular, Mast Cell                 1 (2%)                                                                       
   Lymph Node                                         (8)          (6)          (5)          (6)                                    
      Ectasia                                          1 (13%)                                                                      
      Hyperplasia                                                                1 (20%)                                            
      Iliac, Hematopoietic Cell Proliferation                                    1 (20%)                                            
      Iliac, Hyperplasia                                            2 (33%)                   1 (17%)                               
      Pancreatic, Hyperplasia                                                                 1 (17%)                               
      Renal, Hematopoietic Cell Proliferation                                    1 (20%)                                            
      Renal, Hyperplasia                                            2 (33%)      1 (20%)      2 (33%)                               
   Lymph Node, Bronchial                              (39)         (36)         (40)         (40)                                   
      Hyperplasia                                      4 (10%)      5 (14%)      3 (8%)       2 (5%)                                

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

                                                             Page    4                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
   Lymph Node, Mandibular                             (43)         (34)         (38)         (43)                                   
      Hematopoietic Cell Proliferation                              1 (3%)                                                          
      Hyperplasia                                      1 (2%)       1 (3%)       5 (13%)      5 (12%)                               
   Lymph Node, Mesenteric                             (48)         (46)         (46)         (48)                                   
      Angiectasis                                      1 (2%)                    1 (2%)       2 (4%)                                
      Congestion                                       1 (2%)       1 (2%)                                                          
      Hyperplasia                                      6 (13%)      9 (20%)      3 (7%)       4 (8%)                                
      Infiltration Cellular, Mast Cell                 1 (2%)                                                                       
   Lymph Node, Mediastinal                            (38)         (37)         (35)         (41)                                   
      Hyperplasia                                      6 (16%)      5 (14%)      3 (9%)       2 (5%)                                
   Spleen                                             (50)         (48)         (49)         (50)                                   
      Angiectasis                                                                1 (2%)                                             
      Hematopoietic Cell Proliferation                10 (20%)     13 (27%)     10 (20%)     12 (24%)                               
      Hyperplasia, Lymphoid                            5 (10%)     10 (21%)      6 (12%)      8 (16%)                               
      Infiltration Cellular, Mast Cell                 1 (2%)                                                                       
   Thymus                                             (43)         (39)         (41)         (47)                                   
      Atrophy                                          1 (2%)       2 (5%)       2 (5%)                                             
      Hyperplasia, Lymphoid                            3 (7%)       2 (5%)       6 (15%)      5 (11%)                               
      Infiltration Cellular, Mast Cell                 1 (2%)                                                                       
      Necrosis                                                      1 (3%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (48)         (49)         (50)                                   
      Hyperplasia                                                                             2 (4%)                                
   Skin                                               (49)         (47)         (50)         (50)                                   
      Cyst Epithelial Inclusion                                                               1 (2%)                                
      Inflammation, Chronic                            1 (2%)                                                                       
      Inflammation, Suppurative                        1 (2%)       1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Arthrosis                                        1 (2%)                                                                       
      Fibrous Osteodystrophy                          17 (34%)     18 (36%)     18 (36%)     12 (24%)                               
      Hyperostosis                                                               1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (49)         (50)                                   
      Meninges, Infiltration Cellular, Mononuclear                                                                                  
          Cell                                                      2 (4%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

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

                                                             Page    5                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (49)         (48)         (49)         (50)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
      Metaplasia, Squamous                                          1 (2%)                                                          
   Lung                                               (50)         (50)         (49)         (50)                                   
      Hemorrhage                                       1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Infiltration Cellular, Histiocyte                             1 (2%)       6 (12%)      4 (8%)                                
      Inflammation, Chronic                            2 (4%)                    1 (2%)       1 (2%)                                
      Pigmentation, Hemosiderin                                                  2 (4%)       1 (2%)                                
      Alveolar Epithelium, Hyperplasia                 3 (6%)       1 (2%)       5 (10%)      1 (2%)                                
      Bronchus, Infiltration Cellular, Mixed Cell      1 (2%)                                                                       
      Mediastinum, Hemorrhage, Focal                   1 (2%)                                                                       
      Mediastinum, Infiltration Cellular, Mast Cell    1 (2%)                                                                       
      Mediastinum, Inflammation, Chronic                                                      1 (2%)                                
      Mediastinum, Necrosis                                         1 (2%)                                                          
      Perivascular, Inflammation, Chronic                           1 (2%)                    1 (2%)                                
   Nose                                               (50)         (49)         (50)         (50)                                   
      Inflammation, Chronic, Focal                                               1 (2%)                                             
      Inflammation, Suppurative                        2 (4%)                    4 (8%)       1 (2%)                                
      Glands, Hyperplasia                                                                     1 (2%)                                
      Nasolacrimal Duct, Inflammation, Suppurative     1 (2%)                    3 (6%)       3 (6%)                                
      Olfactory Epithelium, Atrophy, Focal             2 (4%)       6 (12%)                                                         
      Olfactory Epithelium, Degeneration                           22 (45%)     50 (100%)    50 (100%)                              
      Olfactory Epithelium, Metaplasia                              2 (4%)      46 (92%)     48 (96%)                               
      Respiratory Epithelium, Degeneration, Hyaline   16 (32%)     39 (80%)     50 (100%)    50 (100%)                              
      Respiratory Epithelium, Metaplasia, Squamous                               1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                             (1)          (1)                                                 
      Inflammation                                                  1 (100%)     1 (100%)                                           
   Harderian Gland                                    (49)         (49)         (50)         (50)                                   
      Fibrosis, Focal                                                                         1 (2%)                                
      Hyperplasia                                      3 (6%)       2 (4%)       5 (10%)      1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (48)         (49)         (50)                                   
      Amyloid Deposition                                            1 (2%)                                                          
      Hydronephrosis                                                             1 (2%)                                             
      Metaplasia, Osseous                              1 (2%)       2 (4%)       3 (6%)       1 (2%)                                
      Nephropathy                                     12 (24%)      5 (10%)      7 (14%)      7 (14%)                               
      Renal Tubule, Degeneration                                                              1 (2%)                                
      Renal Tubule, Mineralization                                  1 (2%)       1 (2%)                                             
   Urinary Bladder                                    (49)         (47)         (47)         (49)                                   

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

                                                             Page    6                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Inflammation, Suppurative                        1 (2%)       2 (4%)                                                          
      Transitional Epithelium, Hyperplasia                          1 (2%)                                                          
                                                                                                                                    

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

                                                             Page    7                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                14           11           16           16                                     
    Natural Death                                      5            3            4            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                31           36           30           29                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (43)         (47)         (43)         (42)                                   
      Degeneration, Hyaline                            1 (2%)                                                                       
      Hyperplasia                                                   1 (2%)                                                          
   Intestine Large, Cecum                             (46)         (48)         (47)         (46)                                   
      Hemorrhage                                                                 1 (2%)                                             
   Intestine Small, Jejunum                           (45)         (49)         (47)         (46)                                   
      Peyer's Patch, Hyperplasia                                                 1 (2%)                                             
   Liver                                              (50)         (50)         (50)         (50)                                   
      Basophilic Focus                                              1 (2%)       3 (6%)       1 (2%)                                
      Clear Cell Focus                                 2 (4%)       2 (4%)       2 (4%)       8 (16%)                               
      Eosinophilic Focus                              11 (22%)      8 (16%)      9 (18%)     11 (22%)                               
      Hematopoietic Cell Proliferation                              2 (4%)                                                          
      Inflammation, Chronic                                                      2 (4%)       1 (2%)                                
      Mixed Cell Focus                                 1 (2%)                                                                       
      Necrosis                                         4 (8%)       3 (6%)       3 (6%)       2 (4%)                                
      Bile Duct, Cyst                                  1 (2%)                    1 (2%)                                             
      Bile Duct, Degeneration                          1 (2%)                                                                       
   Mesentery                                          (3)                       (6)          (2)                                    
      Fat, Inflammation, Chronic                                                 1 (17%)                                            
      Fat, Necrosis                                    3 (100%)                  3 (50%)      2 (100%)                              
   Pancreas                                           (49)         (50)         (49)         (49)                                   
      Angiectasis                                                                             1 (2%)                                
      Atrophy                                          2 (4%)                                                                       
      Basophilic Focus                                              1 (2%)                                                          
      Cytoplasmic Alteration                                        1 (2%)                                                          
      Duct, Cyst                                       1 (2%)                    1 (2%)                                             
   Stomach, Forestomach                               (49)         (50)         (50)         (48)                                   
      Inflammation, Suppurative                                                               1 (2%)                                
      Epithelium, Hyperplasia                                                    4 (8%)       1 (2%)                                
   Stomach, Glandular                                 (48)         (48)         (48)         (48)                                   
      Inflammation                                                  1 (2%)                                                          
      Ulcer                                            1 (2%)       2 (4%)                                                          
   Tooth                                              (3)          (3)          (1)                                                 
      Developmental Malformation                       2 (67%)      2 (67%)      1 (100%)                                           

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

                                                             Page    8                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Dysplasia                                                     1 (33%)                                                         
      Infiltration Cellular, Mast Cell                 1 (33%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  20 (40%)     20 (40%)     20 (40%)     19 (38%)                               
      Mineralization                                                             1 (2%)                                             
      Artery, Thrombosis                                                         1 (2%)                                             
      Atrium, Thrombosis                               1 (2%)                                                                       
      Endothelium, Hyperplasia                                                   2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (50)         (49)         (48)                                   
      Degeneration                                                               1 (2%)                                             
      Degeneration, Cystic                                                       1 (2%)                                             
      Hematopoietic Cell Proliferation                 1 (2%)                                                                       
      Hemorrhage                                                                 1 (2%)                                             
      Hyperplasia                                      4 (8%)       4 (8%)       6 (12%)      6 (13%)                               
      Hypertrophy                                     22 (45%)     22 (44%)     19 (39%)     22 (46%)                               
      Capsule, Hyperplasia                                                       2 (4%)       2 (4%)                                
   Adrenal Medulla                                    (49)         (50)         (49)         (47)                                   
      Hyperplasia                                      1 (2%)                    1 (2%)       1 (2%)                                
   Islets, Pancreatic                                 (49)         (50)         (49)         (49)                                   
      Hyperplasia                                      5 (10%)      4 (8%)       3 (6%)       4 (8%)                                
   Parathyroid Gland                                  (41)         (34)         (38)         (37)                                   
      Cyst                                                                       1 (3%)                                             
   Pituitary Gland                                    (47)         (50)         (46)         (47)                                   
      Pars Intermedia, Hyperplasia                                  1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (49)         (48)                                   
      Follicular Cell, Hyperplasia                     9 (18%)      3 (6%)       2 (4%)       4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (49)                                   
      Granuloma Sperm                                  1 (2%)       1 (2%)                    1 (2%)                                
      Inflammation, Suppurative                                                  1 (2%)                                             
   Penis                                              (1)          (2)          (3)          (1)                                    

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

                                                             Page    9                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Inflammation, Suppurative                        1 (100%)     2 (100%)     1 (33%)      1 (100%)                              
   Preputial Gland                                    (49)         (50)         (49)         (48)                                   
      Cyst                                             5 (10%)      3 (6%)       2 (4%)       4 (8%)                                
      Inflammation, Chronic                            4 (8%)       3 (6%)       5 (10%)      4 (8%)                                
      Inflammation, Suppurative                                     1 (2%)                                                          
      Bilateral, Cyst                                                            1 (2%)                                             
   Prostate                                           (49)         (50)         (47)         (46)                                   
      Hyperplasia                                      1 (2%)                                                                       
      Inflammation, Suppurative                                     2 (4%)       1 (2%)       2 (4%)                                
   Seminal Vesicle                                    (49)         (49)         (49)         (47)                                   
      Hyperplasia                                                                1 (2%)                                             
      Inflammation                                     1 (2%)                                                                       
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          4 (8%)       2 (4%)       4 (8%)       4 (8%)                                
      Inflammation, Suppurative                                                  1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Hyperplasia                                      1 (2%)       2 (4%)       4 (8%)       1 (2%)                                
   Lymph Node                                         (3)          (1)          (1)          (2)                                    
      Iliac, Hyperplasia                               1 (33%)                                2 (100%)                              
      Renal, Hyperplasia                                                         1 (100%)                                           
   Lymph Node, Bronchial                              (26)         (26)         (24)         (28)                                   
      Hyperplasia                                      1 (4%)       1 (4%)       1 (4%)                                             
   Lymph Node, Mandibular                             (40)         (39)         (37)         (43)                                   
      Hyperplasia                                      2 (5%)       1 (3%)       1 (3%)       4 (9%)                                
   Lymph Node, Mesenteric                             (47)         (46)         (47)         (49)                                   
      Angiectasis                                      3 (6%)       2 (4%)                                                          
      Congestion                                                                 1 (2%)                                             
      Hyperplasia                                      3 (6%)       7 (15%)      2 (4%)       5 (10%)                               
   Lymph Node, Mediastinal                            (35)         (37)         (36)         (40)                                   
      Hyperplasia                                      2 (6%)       1 (3%)                    1 (3%)                                
   Spleen                                             (49)         (50)         (50)         (49)                                   
      Angiectasis                                                   1 (2%)       1 (2%)                                             
      Fibrosis                                                      1 (2%)                                                          
      Fibrosis, Focal                                               1 (2%)                                                          
      Hematopoietic Cell Proliferation                 8 (16%)      9 (18%)     11 (22%)      7 (14%)                               
      Hyperplasia, Lymphoid                                         2 (4%)                                                          
   Thymus                                             (33)         (34)         (33)         (40)                                   
      Necrosis                                         1 (3%)       1 (3%)                    1 (3%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

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

                                                             Page   10                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (49)         (49)         (49)         (48)                                   
      Inflammation, Suppurative                        5 (10%)      1 (2%)       2 (4%)                                             
      Prepuce, Inflammation, Suppurative               6 (12%)      3 (6%)       8 (16%)      3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Hyperostosis                                     1 (2%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (49)         (48)                                   
      Inflammation, Suppurative                        1 (2%)                                 1 (2%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)       1 (2%)                                             
      Infiltration Cellular, Histiocyte                7 (14%)      2 (4%)       3 (6%)       6 (12%)                               
      Inflammation, Chronic                                         1 (2%)                                                          
      Pigmentation, Hemosiderin                                     1 (2%)       3 (6%)                                             
      Thrombosis                                                                 1 (2%)                                             
      Alveolar Epithelium, Hyperplasia                 1 (2%)       1 (2%)       3 (6%)       1 (2%)                                
      Mediastinum, Inflammation, Chronic                                                      1 (2%)                                
      Perivascular, Inflammation, Chronic              2 (4%)                                                                       
   Nose                                               (50)         (49)         (50)         (50)                                   
      Inflammation, Suppurative                        1 (2%)       5 (10%)      3 (6%)       1 (2%)                                
      Nasolacrimal Duct, Inflammation, Suppurative     2 (4%)       3 (6%)      10 (20%)     10 (20%)                               
      Olfactory Epithelium, Atrophy, Focal             3 (6%)       8 (16%)                                                         
      Olfactory Epithelium, Degeneration                           10 (20%)     50 (100%)    50 (100%)                              
      Olfactory Epithelium, Metaplasia                              1 (2%)      41 (82%)     49 (98%)                               
      Respiratory Epithelium, Degeneration, Hyaline    5 (10%)      5 (10%)     50 (100%)    50 (100%)                              
      Respiratory Epithelium, Metaplasia, Squamous                  2 (4%)                                                          
   Trachea                                            (49)         (49)         (49)         (49)                                   
      Metaplasia, Squamous                                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

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

                                                             Page   11                                                              
NTP Experiment-Test: 05200-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:51  
____________________________________________________________________________________________________________________________________

         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                             (1)          (3)          (5)                                    
      Inflammation                                                               3 (100%)     4 (80%)                               
   Harderian Gland                                    (49)         (50)         (50)         (49)                                   
      Hyperplasia                                      2 (4%)       2 (4%)       6 (12%)      2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (49)         (49)                                   
      Amyloid Deposition                                                         1 (2%)                                             
      Hydronephrosis                                   4 (8%)       1 (2%)       3 (6%)                                             
      Inflammation, Suppurative                        1 (2%)       4 (8%)       2 (4%)       2 (4%)                                
      Metaplasia, Osseous                              1 (2%)       4 (8%)       1 (2%)       1 (2%)                                
      Nephropathy                                     35 (70%)     34 (68%)     33 (67%)     41 (84%)                               
      Cortex, Cyst                                                  1 (2%)       1 (2%)                                             
      Pelvis, Necrosis                                                                        1 (2%)                                
      Renal Tubule, Hyperplasia                        2 (4%)       5 (10%)      2 (4%)       3 (6%)                                
      Renal Tubule, Mineralization                                               2 (4%)                                             
   Ureter                                                                                    (1)                                    
      Inflammation, Suppurative                                                               1 (100%)                              
      Necrosis                                                                                1 (100%)                              
   Urethra                                                         (1)                                                              
      Inflammation, Suppurative                                     1 (100%)                                                        
   Urinary Bladder                                    (48)         (50)         (49)         (48)                                   
      Calculus Gross Observation                       1 (2%)                                                                       
      Inflammation, Chronic                                                      1 (2%)                                             
      Inflammation, Suppurative                        1 (2%)       4 (8%)       2 (4%)       3 (6%)                                
      Transitional Epithelium, Hyperplasia                          1 (2%)                    2 (4%)                                
                                                                                                                                    

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

                                                             Page   12                                                              
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