Skip to Main Navigation
Skip to Page Content
Share This:
https://ntp.niehs.nih.gov/go/6094

TDMS Study 05200-05 Pathology Tables

NTP Experiment-Test: 05200-05         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: 05:30:28




       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: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      5            5            2            2                                     
    Moribund Sacrifice                                17           26           18           25                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                28           19           30           23                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)       1 (2%)       4 (8%)       5 (10%)                               
      Basophilic Focus                                41 (82%)     42 (84%)     41 (82%)     41 (82%)                               
      Clear Cell Focus                                 6 (12%)      9 (18%)      9 (18%)      7 (14%)                               
      Degeneration, Cystic                             1 (2%)                    1 (2%)                                             
      Degeneration, Fatty                              9 (18%)      7 (14%)      8 (16%)      5 (10%)                               
      Eosinophilic Focus                               2 (4%)       2 (4%)       1 (2%)       1 (2%)                                
      Hepatodiaphragmatic Nodule                       7 (14%)      4 (8%)       3 (6%)       5 (10%)                               
      Inflammation, Granulomatous                      1 (2%)                                 1 (2%)                                
      Mixed Cell Focus                                12 (24%)     15 (30%)     11 (22%)     17 (34%)                               
      Necrosis                                         1 (2%)                                 1 (2%)                                
      Regeneration                                     2 (4%)                                                                       
      Bile Duct, Hyperplasia                          10 (20%)      7 (14%)     12 (24%)      9 (18%)                               
      Centrilobular, Necrosis                          1 (2%)                                                                       
   Mesentery                                          (10)         (11)         (12)         (14)                                   
      Fat, Necrosis                                    7 (70%)     10 (91%)     10 (83%)     11 (79%)                               
   Pancreas                                           (50)         (50)         (50)         (50)                                   
      Atrophy                                         20 (40%)     15 (30%)     20 (40%)     24 (48%)                               
      Basophilic Focus                                 1 (2%)       2 (4%)       2 (4%)       1 (2%)                                
      Hyperplasia                                      1 (2%)                                 1 (2%)                                
      Metaplasia, Hepatocyte                                        1 (2%)                                                          
      Artery, Inflammation                             1 (2%)                                 1 (2%)                                
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)       1 (2%)       1 (2%)                                             
      Basophilic Focus                                              2 (4%)                                                          
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                                               1 (2%)                                             
      Hyperplasia, Squamous                                                      1 (2%)                                             
      Inflammation, Acute                              2 (4%)       1 (2%)       4 (8%)       1 (2%)                                
      Mineralization                                                                          1 (2%)                                
      Necrosis                                         4 (8%)       3 (6%)       5 (10%)      6 (12%)                               
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
      Inflammation, Acute                                                        1 (2%)                                             
      Mineralization                                   1 (2%)       1 (2%)       1 (2%)       1 (2%)                                

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

                                                             Page    2                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Necrosis                                         2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
   Tooth                                                           (1)                                                              
      Inflammation, Chronic Active                                  1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  42 (84%)     31 (62%)     34 (68%)     39 (78%)                               
      Artery, Mineralization                                        1 (2%)                                                          
      Atrium, Thrombosis                                                                      1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Hematopoietic Cell Proliferation                              1 (2%)                                                          
      Hyperplasia                                      6 (12%)     15 (30%)     12 (24%)     13 (26%)                               
      Hypertrophy                                     16 (32%)     12 (24%)     14 (28%)     12 (24%)                               
      Necrosis                                                                                1 (2%)                                
      Vacuolization Cytoplasmic                                     1 (2%)                    2 (4%)                                
   Adrenal Medulla                                    (49)         (50)         (49)         (50)                                   
      Hyperplasia                                      3 (6%)       4 (8%)       9 (18%)      8 (16%)                               
   Islets, Pancreatic                                 (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      2 (4%)                                                                       
   Parathyroid Gland                                  (50)         (49)         (50)         (48)                                   
      Hyperplasia                                      1 (2%)       1 (2%)                                                          
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                                   1 (2%)                                                          
      Pars Distalis, Angiectasis                       1 (2%)                                                                       
      Pars Distalis, Hyperplasia                      13 (26%)      8 (16%)      9 (18%)      9 (18%)                               
   Thyroid Gland                                      (50)         (50)         (50)         (49)                                   
      C-Cell, Hyperplasia                             41 (82%)     47 (94%)     49 (98%)     42 (86%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (47)         (46)         (47)         (48)                                   
      Hyperplasia                                                                             1 (2%)                                
      Inflammation, Chronic Active                     4 (9%)       6 (13%)      4 (9%)       2 (4%)                                
   Ovary                                              (50)         (50)         (50)         (50)                                   

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

                                                             Page    3                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Cyst                                             1 (2%)       2 (4%)       5 (10%)      3 (6%)                                
      Inflammation, Granulomatous                                                1 (2%)                                             
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             1 (2%)                                                                       
      Hydrometra                                                                 1 (2%)                                             
      Hyperplasia                                      1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia, Reticulum Cell                      1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
   Lymph Node                                         (7)          (6)          (9)          (3)                                    
      Iliac, Pigmentation                              1 (14%)                                1 (33%)                               
      Pancreatic, Hemorrhage                                        1 (17%)      1 (11%)                                            
      Pancreatic, Infiltration Cellular, Eosinophil                                           1 (33%)                               
      Pancreatic, Inflammation, Granulomatous                                                 1 (33%)                               
      Renal, Hemorrhage                                1 (14%)                   1 (11%)      1 (33%)                               
      Renal, Pigmentation                                                        1 (11%)                                            
   Lymph Node, Bronchial                              (48)         (49)         (47)         (48)                                   
      Infiltration Cellular, Eosinophil                                                       1 (2%)                                
      Inflammation, Granulomatous                                                             1 (2%)                                
   Lymph Node, Mandibular                             (49)         (48)         (48)         (47)                                   
      Hemorrhage                                                                              1 (2%)                                
      Infiltration Cellular, Plasma Cell                                         2 (4%)       1 (2%)                                
   Lymph Node, Mesenteric                             (50)         (50)         (49)         (50)                                   
      Hemorrhage                                       1 (2%)       1 (2%)                    1 (2%)                                
      Infiltration Cellular, Eosinophil                                                       1 (2%)                                
      Inflammation, Granulomatous                                                             1 (2%)                                
   Lymph Node, Mediastinal                            (48)         (49)         (50)         (46)                                   
      Hemorrhage                                       1 (2%)       3 (6%)       1 (2%)       2 (4%)                                
      Inflammation, Granulomatous                                   1 (2%)                                                          
   Spleen                                             (50)         (49)         (50)         (50)                                   
      Fibrosis                                         2 (4%)       1 (2%)       4 (8%)       1 (2%)                                
      Hematopoietic Cell Proliferation                              3 (6%)                    2 (4%)                                
      Thrombosis                                       1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Galactocele                                      3 (6%)       1 (2%)       3 (6%)       7 (14%)                               
      Hyperplasia                                                                1 (2%)                                             
      Hyperplasia, Atypical                           12 (24%)     17 (34%)     14 (28%)     15 (30%)                               
      Hyperplasia, Lobular                                                                    2 (4%)                                
      Inflammation, Granulomatous                                   1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)       1 (2%)                                             

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

                                                             Page    4                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
   Skin                                               (50)         (50)         (48)         (49)                                   
      Hyperkeratosis                                                1 (2%)                                                          
      Inflammation, Acute                              1 (2%)                                                                       
      Inflammation, Chronic Active                     1 (2%)       2 (4%)                    1 (2%)                                
      Inflammation, Granulomatous                                   1 (2%)                                                          
      Sebaceous Gland, Hypertrophy                                  1 (2%)                                                          
      Vulva, Inflammation, Acute                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                                        1 (2%)                                                          
      Hyperostosis                                     3 (6%)       1 (2%)                    1 (2%)                                
      Cranium, Hyperostosis                                                      1 (2%)                                             
      Femur, Hyperostosis                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)       2 (4%)                    1 (2%)                                
      Hydrocephalus                                    1 (2%)       1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (49)                                   
      Metaplasia, Squamous                             1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                                                 1 (2%)                                             
      Fibrosis, Focal                                               1 (2%)                                                          
      Fibrosis, Multifocal                                                                    1 (2%)                                
      Hemorrhage                                                    1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     2 (4%)       2 (4%)       1 (2%)       1 (2%)                                
      Mineralization                                                1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia                 6 (12%)     11 (22%)      7 (14%)      7 (14%)                               
      Artery, Mediastinum, Inflammation                                                       1 (2%)                                
      Artery, Mediastinum, Mineralization                           1 (2%)                                                          
      Bronchiole, Hyperplasia                                       1 (2%)                                                          
      Bronchiole, Metaplasia                                                                  1 (2%)                                
   Nose                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                  3 (6%)       2 (4%)                                             
      Inflammation, Suppurative                        4 (8%)       2 (4%)                                                          
      Thrombosis                                                    1 (2%)                    1 (2%)                                
      Nasolacrimal Duct, Inflammation, Suppurative     5 (10%)      4 (8%)       6 (12%)      2 (4%)                                
____________________________________________________________________________________________________________________________________

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

                                                             Page    5                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (2)          (1)          (2)          (4)                                    
      Cataract                                         1 (50%)                   1 (50%)      3 (75%)                               
      Degeneration                                     1 (50%)      1 (100%)                  1 (25%)                               
      Retina, Atrophy                                                                         1 (25%)                               
   Harderian Gland                                    (3)                                                                           
      Hemorrhage                                       1 (33%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Infarct                                          1 (2%)                                 1 (2%)                                
      Mineralization                                                1 (2%)                                                          
      Nephropathy                                     49 (98%)     49 (98%)     48 (96%)     49 (98%)                               
      Renal Tubule, Hyperplasia                                     1 (2%)                    1 (2%)                                
   Urinary Bladder                                    (50)         (50)         (49)         (50)                                   
      Transitional Epithelium, Hyperplasia             1 (2%)                                                                       
                                                                                                                                    

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

                                                             Page    6                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 

  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                33           31           34           39                                     
    Natural Death                                      4            3            2            3                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                13           16           14            8                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (50)         (50)         (50)                                   
      Diverticulum                                                                            1 (2%)                                
      Inflammation, Acute                                           1 (2%)                    1 (2%)                                
      Necrosis                                         1 (2%)       1 (2%)                                                          
   Intestine Small, Duodenum                          (50)         (50)         (50)         (49)                                   
      Necrosis                                         1 (2%)       1 (2%)                                                          
   Intestine Small, Jejunum                           (50)         (50)         (50)         (50)                                   
      Diverticulum                                     1 (2%)                                                                       
      Inflammation, Acute                                           1 (2%)                                                          
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      1 (2%)       3 (6%)                    3 (6%)                                
      Basophilic Focus                                16 (32%)     19 (38%)     20 (40%)     23 (46%)                               
      Clear Cell Focus                                 3 (6%)       5 (10%)     10 (20%)      6 (12%)                               
      Cyst                                                          2 (4%)       1 (2%)                                             
      Degeneration, Cystic                            19 (38%)     15 (30%)     16 (32%)     22 (44%)                               
      Degeneration, Fatty                              6 (12%)      6 (12%)      2 (4%)       8 (16%)                               
      Eosinophilic Focus                               2 (4%)       4 (8%)       4 (8%)       3 (6%)                                
      Hepatodiaphragmatic Nodule                       4 (8%)       4 (8%)       2 (4%)       2 (4%)                                
      Inflammation, Suppurative                                                  1 (2%)                                             
      Mixed Cell Focus                                 7 (14%)      6 (12%)      9 (18%)      7 (14%)                               
      Necrosis                                         1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
      Regeneration                                     2 (4%)                    1 (2%)       2 (4%)                                
      Thrombosis                                                                 1 (2%)                                             
      Bile Duct, Hyperplasia                          44 (88%)     43 (86%)     47 (94%)     43 (86%)                               
      Centrilobular, Necrosis                          7 (14%)      1 (2%)       1 (2%)       2 (4%)                                
   Mesentery                                          (15)         (13)         (10)         (8)                                    
      Infiltration Cellular                                         1 (8%)                                                          
      Artery, Inflammation                                          2 (15%)                                                         
      Artery, Mineralization                                        2 (15%)      1 (10%)                                            
      Fat, Hemorrhage                                               1 (8%)                    1 (13%)                               
      Fat, Necrosis                                   12 (80%)      7 (54%)      9 (90%)      6 (75%)                               
   Oral Mucosa                                        (1)          (2)          (1)                                                 
      Gingival, Hyperplasia                                         1 (50%)                                                         
      Gingival, Inflammation, Chronic Active                        1 (50%)                                                         

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

                                                             Page    7                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Pharyngeal, Hyperplasia, Squamous                1 (100%)                                                                     
   Pancreas                                           (50)         (50)         (50)         (50)                                   
      Atrophy                                         27 (54%)     28 (56%)     34 (68%)     32 (64%)                               
      Basophilic Focus                                              3 (6%)       7 (14%)      3 (6%)                                
      Hyperplasia                                      2 (4%)       3 (6%)       5 (10%)      4 (8%)                                
      Hyperplasia, Focal                                            1 (2%)                                                          
      Hypertrophy                                                                1 (2%)                                             
      Artery, Inflammation                                          3 (6%)                                                          
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Degeneration, Fatty                                           1 (2%)                                                          
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                                               1 (2%)                                             
      Hyperplasia, Squamous                                         3 (6%)       1 (2%)       1 (2%)                                
      Inflammation, Acute                              3 (6%)       2 (4%)                    8 (16%)                               
      Mineralization                                                             1 (2%)                                             
      Necrosis                                         6 (12%)      4 (8%)       3 (6%)       9 (18%)                               
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
      Inflammation, Acute                              1 (2%)                    1 (2%)       2 (4%)                                
      Inflammation, Chronic                                                                   1 (2%)                                
      Mineralization                                                4 (8%)       2 (4%)                                             
      Necrosis                                         3 (6%)       1 (2%)       1 (2%)       3 (6%)                                
   Tooth                                              (1)          (2)          (3)                                                 
      Developmental Malformation                                                 1 (33%)                                            
      Foreign Body                                                  1 (50%)                                                         
      Inflammation, Chronic Active                     1 (100%)     2 (100%)     2 (67%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                 (1)                                                 
      Aorta, Mineralization                                                      1 (100%)                                           
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  45 (90%)     49 (98%)     47 (94%)     47 (94%)                               
      Artery, Mineralization                                        1 (2%)       1 (2%)                                             
      Atrium, Thrombosis                               5 (10%)                   3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                                                       1 (2%)                                
      Atrophy                                                       3 (6%)       1 (2%)       2 (4%)                                
      Hyperplasia                                     24 (48%)     19 (38%)     22 (44%)     22 (44%)                               
      Hypertrophy                                      6 (12%)     10 (20%)     11 (22%)      8 (16%)                               
      Necrosis                                         1 (2%)                    2 (4%)       1 (2%)                                
      Thrombosis                                                                 1 (2%)                                             
      Vacuolization Cytoplasmic                        1 (2%)       1 (2%)       4 (8%)       3 (6%)                                

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

                                                             Page    8                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                     20 (40%)     23 (46%)     27 (54%)     22 (44%)                               
      Necrosis                                         1 (2%)                                 1 (2%)                                
   Islets, Pancreatic                                 (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       2 (4%)                    1 (2%)                                
   Parathyroid Gland                                  (47)         (49)         (49)         (48)                                   
      Hyperplasia                                      8 (17%)      4 (8%)       5 (10%)      7 (15%)                               
   Pituitary Gland                                    (50)         (47)         (50)         (49)                                   
      Pars Distalis, Hyperplasia                       7 (14%)      7 (15%)      9 (18%)      8 (16%)                               
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      C-Cell, Hyperplasia                             34 (68%)     37 (74%)     34 (68%)     41 (82%)                               
      Follicular Cell, Hyperplasia                     1 (2%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                                                         2 (4%)                                
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                                          1 (2%)                    1 (2%)                                
      Inflammation, Chronic Active                     5 (10%)      3 (6%)       3 (6%)       9 (18%)                               
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     7 (14%)      9 (18%)      2 (4%)       8 (16%)                               
      Inflammation, Suppurative                        4 (8%)       2 (4%)       3 (6%)       6 (12%)                               
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                                            1 (2%)                                
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          4 (8%)       7 (14%)      5 (10%)      6 (12%)                               
      Artery, Inflammation                                          4 (8%)                    3 (6%)                                
      Interstitial Cell, Hyperplasia                  17 (34%)     17 (34%)     12 (24%)     16 (32%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Congestion                                                    1 (2%)                                                          
      Myelofibrosis                                    2 (4%)                    1 (2%)       1 (2%)                                
      Thrombosis                                       1 (2%)       1 (2%)                                                          
   Lymph Node                                         (17)         (13)         (17)         (13)                                   
      Pancreatic, Inflammation, Granulomatous          1 (6%)                                                                       
      Renal, Hemorrhage                                             1 (8%)       2 (12%)      2 (15%)                               
      Renal, Infiltration Cellular, Plasma Cell        1 (6%)                                 1 (8%)                                

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

                                                             Page    9                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Renal, Inflammation, Granulomatous               1 (6%)       1 (8%)                                                          
      Renal, Pigmentation                              2 (12%)      1 (8%)       2 (12%)      1 (8%)                                
   Lymph Node, Mandibular                             (48)         (48)         (48)         (49)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Infiltration Cellular, Plasma Cell               1 (2%)       3 (6%)       5 (10%)                                            
      Inflammation, Granulomatous                      1 (2%)                                                                       
   Lymph Node, Mesenteric                             (50)         (50)         (48)         (50)                                   
      Hemorrhage                                                    1 (2%)       1 (2%)                                             
      Inflammation, Acute                                           1 (2%)                                                          
      Inflammation, Granulomatous                                   1 (2%)       1 (2%)                                             
   Lymph Node, Mediastinal                            (50)         (45)         (50)         (47)                                   
      Hemorrhage                                       2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Granulomatous                                                             1 (2%)                                
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Fibrosis                                        14 (28%)     20 (40%)     26 (52%)     19 (38%)                               
      Hematopoietic Cell Proliferation                 1 (2%)       1 (2%)                    1 (2%)                                
      Hemorrhage                                                    1 (2%)                                                          
      Necrosis                                         1 (2%)                                 1 (2%)                                
   Thymus                                             (45)         (45)         (48)         (46)                                   
      Artery, Inflammation                                          1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (28)         (27)         (31)         (28)                                   
      Galactocele                                      2 (7%)                    2 (6%)       3 (11%)                               
      Hyperplasia                                      1 (4%)                                                                       
      Hyperplasia, Atypical                            1 (4%)                                 1 (4%)                                
      Duct, Inflammation, Chronic                      1 (4%)                                                                       
   Skin                                               (50)         (49)         (50)         (50)                                   
      Cyst                                             2 (4%)       1 (2%)                                                          
      Hyperkeratosis                                   3 (6%)       3 (6%)                    1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       3 (6%)       1 (2%)       1 (2%)                                
      Inflammation, Granulomatous                      2 (4%)       2 (4%)       2 (4%)       1 (2%)                                
      Prepuce, Inflammation, Acute                     2 (4%)                    1 (2%)                                             
      Subcutaneous Tissue, Cyst Epithelial                                                                                          
          Inclusion                                    1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                                        3 (6%)       4 (8%)       2 (4%)                                
      Hyperostosis                                     1 (2%)       2 (4%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

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

                                                             Page   10                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Degeneration                                                               1 (2%)                                             
      Hemorrhage                                       1 (2%)                    1 (2%)       1 (2%)                                
      Hydrocephalus                                    1 (2%)                                 2 (4%)                                
      Inflammation, Chronic                                                      1 (2%)                                             
      Mineralization                                                             1 (2%)                                             
      Artery, Inflammation                                          1 (2%)                                                          
   Peripheral Nerve                                                                          (1)                                    
      Radicular Neuropathy                                                                    1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (50)                                   
      Metaplasia, Squamous                             1 (2%)                                 1 (2%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)       1 (2%)                    1 (2%)                                
      Congestion, Chronic                              1 (2%)                                                                       
      Hemorrhage                                       1 (2%)                                                                       
      Inflammation, Chronic Active                     2 (4%)       2 (4%)       1 (2%)                                             
      Metaplasia, Osseous                                                        1 (2%)       1 (2%)                                
      Mineralization                                                             1 (2%)                                             
      Alveolar Epithelium, Hyperplasia                 4 (8%)       8 (16%)     10 (20%)      9 (18%)                               
      Artery, Mediastinum, Inflammation                             2 (4%)                                                          
   Nose                                               (50)         (50)         (50)         (50)                                   
      Foreign Body                                                  1 (2%)       3 (6%)       1 (2%)                                
      Inflammation, Chronic Active                     4 (8%)       1 (2%)       3 (6%)       2 (4%)                                
      Inflammation, Suppurative                       10 (20%)      3 (6%)       3 (6%)       5 (10%)                               
      Thrombosis                                       6 (12%)      3 (6%)       5 (10%)      2 (4%)                                
      Nasolacrimal Duct, Inflammation, Suppurative                  1 (2%)       3 (6%)                                             
      Olfactory Epithelium, Foreign Body                            1 (2%)                                                          
      Olfactory Epithelium, Inflammation,                                                                                           
          Suppurative                                               1 (2%)                                                          
   Trachea                                            (50)         (50)         (50)         (50)                                   
      Mineralization                                                             1 (2%)                                             
      Epithelium, Hyperplasia                                       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (2)          (1)          (1)          (1)                                    
      Cataract                                                                                1 (100%)                              
      Degeneration                                     2 (100%)     1 (100%)     1 (100%)                                           
      Retina, Atrophy                                                                         1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    

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

                                                             Page   11                                                              
NTP Experiment-Test: 05200-05         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: 05:30:28  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      94 PPM       188 PPM      375 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Infarct                                          2 (4%)                    1 (2%)                                             
      Mineralization                                                1 (2%)       2 (4%)                                             
      Nephropathy                                     50 (100%)    50 (100%)    50 (100%)    50 (100%)                              
      Artery, Inflammation                                          1 (2%)                                                          
      Pelvis, Dilatation                                                         1 (2%)                                             
      Renal Tubule, Hyperplasia                                     3 (6%)       2 (4%)       1 (2%)                                
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)                                                          
      Transitional Epithelium, Hyperplasia                                       1 (2%)                                             
                                                                                                                                    

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

                                                             Page   12                                                              
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------