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TDMS Study 88050-05 Pathology Tables

NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00
Route: GAVAGE                                                                                                     Time: 14:18:49

                                                  FINAL#1 2 YEAR CHRONIC RATS




       Facility:  Battelle Columbus Laboratory

       Chemical CAS #:  126-98-7

       Lock Date:  05/05/99

       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: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 


  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 4           10            9            7                                     
    Natural Death                                      7            6            6            7                                     
    Dosing Accident                                    1            1            1                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                38           33           34           35                                     
    Natural Death                                                                             1                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (50)         (50)         (50)                                   
      Periesophageal Tissue, Hemorrhage                             1 (2%)       2 (4%)                                             
   Intestine Large, Rectum                            (50)         (50)         (50)         (50)                                   
      Parasite Metazoan                                2 (4%)       5 (10%)      5 (10%)      4 (8%)                                
   Intestine Large, Cecum                             (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                                            1 (2%)                                
   Intestine Small, Duodenum                          (50)         (50)         (50)         (50)                                   
      Fibrosis                                                                                1 (2%)                                
   Liver                                              (50)         (49)         (48)         (50)                                   
      Angiectasis                                                   1 (2%)       2 (4%)       1 (2%)                                
      Basophilic Focus                                43 (86%)     43 (88%)     35 (73%)     39 (78%)                               
      Clear Cell Focus                                 4 (8%)       2 (4%)       1 (2%)       3 (6%)                                
      Degeneration                                                               1 (2%)                                             
      Degeneration, Cystic                             1 (2%)                    1 (2%)                                             
      Eosinophilic Focus                                                         3 (6%)                                             
      Fatty Change                                    21 (42%)     13 (27%)     11 (23%)      7 (14%)                               
      Hepatodiaphragmatic Nodule                       9 (18%)      7 (14%)      8 (17%)     12 (24%)                               
      Hyperplasia                                                   1 (2%)                                                          
      Inflammation, Chronic Active                    31 (62%)     27 (55%)     27 (56%)     27 (54%)                               
      Mixed Cell Focus                                 2 (4%)       7 (14%)      8 (17%)      5 (10%)                               
      Necrosis                                         2 (4%)       3 (6%)       1 (2%)                                             
      Thrombosis                                       2 (4%)                    3 (6%)                                             
      Vacuolization Cytoplasmic                        7 (14%)     14 (29%)     17 (35%)     30 (60%)                               
      Bile Duct, Hyperplasia                          14 (28%)      5 (10%)     13 (27%)      9 (18%)                               
   Mesentery                                          (7)          (2)          (8)          (4)                                    
      Fat, Inflammation, Chronic Active                5 (71%)      1 (50%)      2 (25%)      1 (25%)                               
      Fat, Necrosis                                    1 (14%)      1 (50%)      4 (50%)      2 (50%)                               
   Pancreas                                           (50)         (50)         (50)         (50)                                   
      Cytoplasmic Alteration                                                     1 (2%)                                             
      Hyperplasia                                      1 (2%)                    1 (2%)       1 (2%)                                
      Acinus, Atrophy                                  8 (16%)      4 (8%)       7 (14%)     10 (20%)                               
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Edema                                            1 (2%)       1 (2%)                                                          
      Hyperplasia                                      1 (2%)       1 (2%)                    1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       2 (4%)       1 (2%)                                             
      Ulcer                                                                      1 (2%)                                             
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
      Erosion                                          1 (2%)       1 (2%)       2 (4%)       5 (10%)                               
      Mineralization                                                             1 (2%)                                             
      Ulcer                                            1 (2%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  24 (48%)     19 (38%)     16 (32%)     21 (42%)                               
      Fibrosis                                         1 (2%)                                                                       
      Thrombosis                                                    1 (2%)       2 (4%)       1 (2%)                                
      Epicardium, Inflammation, Chronic Active         1 (2%)                                                                       
      Pericardium, Inflammation, Chronic Active                                  1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Angiectasis                                     23 (46%)      6 (12%)     12 (24%)     19 (38%)                               
      Degeneration                                                               1 (2%)                                             
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia                                      7 (14%)      6 (12%)     10 (20%)      7 (14%)                               
      Hypertrophy                                                   1 (2%)                                                          
      Necrosis                                                                                2 (4%)                                
      Thrombosis                                                                              1 (2%)                                
      Vacuolization Cytoplasmic                        4 (8%)       1 (2%)       2 (4%)       6 (12%)                               
      Capsule, Fibrosis                                1 (2%)                                                                       
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      2 (4%)                    3 (6%)       1 (2%)                                
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                      6 (12%)      4 (8%)       3 (6%)       5 (10%)                               
      Cyst                                            19 (38%)     13 (26%)     14 (28%)     15 (30%)                               
      Hyperplasia                                     20 (40%)     23 (46%)     16 (32%)     16 (32%)                               
      Craniopharyngeal Duct, Hyperplasia               1 (2%)                                                                       
      Pars Nervosa, Hyperplasia                        1 (2%)                                                                       
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      C-Cell, Hyperplasia                             36 (72%)     25 (50%)     37 (74%)     32 (64%)                               
____________________________________________________________________________________________________________________________________

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (49)         (48)         (50)         (48)                                   
      Cyst                                             1 (2%)       4 (8%)       5 (10%)      1 (2%)                                
      Hyperplasia                                     10 (20%)      7 (15%)     10 (20%)      2 (4%)                                
      Inflammation, Chronic Active                     6 (12%)      2 (4%)       5 (10%)      8 (17%)                               
   Ovary                                              (50)         (50)         (50)         (50)                                   
      Atrophy                                                       1 (2%)                                                          
      Cyst                                                                       1 (2%)                                             
      Mineralization                                                             1 (2%)                                             
      Follicle, Cyst                                   3 (6%)       1 (2%)       1 (2%)       1 (2%)                                
      Periovarian Tissue, Cyst                         4 (8%)       3 (6%)       2 (4%)       3 (6%)                                
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                                              1 (2%)                                
      Hydrometra                                       2 (4%)       2 (4%)       2 (4%)       2 (4%)                                
      Inflammation, Chronic Active                                  2 (4%)                                                          
      Cervix, Fibrosis                                 1 (2%)                    1 (2%)       1 (2%)                                
      Cervix, Inflammation, Chronic Active                                       3 (6%)       1 (2%)                                
      Endometrium, Hyperplasia, Cystic                 4 (8%)       1 (2%)       3 (6%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)       1 (2%)                    1 (2%)                                
      Hyperplasia                                     12 (24%)     11 (22%)     12 (24%)     25 (50%)                               
      Myelofibrosis                                    1 (2%)                                                                       
   Lymph Node                                         (6)          (1)          (5)          (1)                                    
      Mediastinal, Hyperplasia                                                   1 (20%)                                            
   Lymph Node, Mandibular                             (50)         (49)         (50)         (50)                                   
      Ectasia                                          1 (2%)       1 (2%)                    1 (2%)                                
      Hyperplasia                                                                1 (2%)                                             
   Lymph Node, Mesenteric                             (50)         (50)         (50)         (50)                                   
      Ectasia                                                       1 (2%)                    1 (2%)                                
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Accessory Spleen                                                                        1 (2%)                                
      Fibrosis                                         1 (2%)       1 (2%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                 1 (2%)       8 (16%)      7 (14%)      5 (10%)                               
      Capsule, Necrosis                                                                       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Galactocele                                     13 (26%)      9 (18%)      9 (18%)      9 (18%)                               
      Hyperplasia                                      8 (16%)     11 (22%)      9 (18%)      6 (12%)                               
      Inflammation, Chronic Active                                  1 (2%)                                                          
   Skin                                               (50)         (50)         (50)         (50)                                   
      Parakeratosis                                                 1 (2%)                                                          
      Ulcer                                                         1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Osteosclerosis                                   1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                                                 1 (2%)                                             
      Hemorrhage                                                    1 (2%)       2 (4%)                                             
      Inflammation, Chronic Active                     5 (10%)      4 (8%)       4 (8%)       4 (8%)                                
      Necrosis                                                                   1 (2%)                                             
      Pigmentation                                                               1 (2%)                                             
      Alveolar Epithelium, Hyperplasia                 6 (12%)      3 (6%)       4 (8%)       6 (12%)                               
      Mediastinum, Inflammation                                                  1 (2%)                                             
   Nose                                               (50)         (50)         (50)         (50)                                   
      Inflammation                                                  1 (2%)                                                          
      Inflammation, Chronic Active                     1 (2%)                    2 (4%)       1 (2%)                                
      Thrombosis                                                    3 (6%)       1 (2%)       2 (4%)                                
      Olfactory Epithelium, Atrophy                                              1 (2%)      19 (38%)                               
      Olfactory Epithelium, Metaplasia                                                       47 (94%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (4)          (1)          (3)          (1)                                    
      Cataract                                         4 (100%)     1 (100%)     3 (100%)     1 (100%)                              
      Lens, Mineralization                             3 (75%)                   2 (67%)                                            
      Retina, Degeneration                             3 (75%)      1 (100%)     3 (100%)     1 (100%)                              
   Zymbal's Gland                                                               (1)                                                 

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
SPECIAL SENSES SYSTEM - CONT                                                                                                        
      Inflammation, Chronic Active                                               1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Accumulation, Hyaline Droplet                    2 (4%)                    1 (2%)                                             
      Congestion                                                    1 (2%)                                                          
      Hydronephrosis                                                                          1 (2%)                                
      Inflammation, Chronic Active                     3 (6%)       9 (18%)      5 (10%)      3 (6%)                                
      Necrosis                                         1 (2%)                                                                       
      Nephropathy                                     29 (58%)     27 (54%)     29 (58%)     25 (50%)                               
      Pigmentation                                     3 (6%)       3 (6%)       2 (4%)                                             
      Renal Tubule, Hyperplasia                                     1 (2%)                                                          
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                    1 (2%)                                                          
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       1 (2%)                                             
      Transitional Epithelium, Hyperplasia                                                    1 (2%)                                
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 


  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                     12            3            6            6                                     
    Moribund Sacrifice                                13           13            9           12                                     
    Dosing Accident                                                                           1                                     
  Survivors                                                                                                                         
    Natural Death                                                                1                                                  
    Terminal Sacrifice                                25           34           34           31                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                               1 (2%)                                             
      Parasite Metazoan                                             1 (2%)       1 (2%)                                             
      Pigmentation                                                               1 (2%)                                             
   Intestine Large, Rectum                            (50)         (50)         (50)         (50)                                   
      Parasite Metazoan                               10 (20%)      8 (16%)      7 (14%)      5 (10%)                               
   Intestine Large, Cecum                             (49)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Epithelium, Atrophy                                                        1 (2%)                                             
   Intestine Small, Duodenum                          (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                  1 (2%)       1 (2%)                                             
      Parasite Metazoan                                             1 (2%)                                                          
   Intestine Small, Jejunum                           (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                                               2 (4%)                                             
   Intestine Small, Ileum                             (50)         (50)         (49)         (50)                                   
      Inflammation, Chronic Active                                               2 (4%)                                             
      Parasite Metazoan                                1 (2%)                                                                       
   Liver                                              (50)         (50)         (50)         (49)                                   
      Angiectasis                                      2 (4%)       4 (8%)       7 (14%)      4 (8%)                                
      Basophilic Focus                                26 (52%)     33 (66%)     35 (70%)     13 (27%)                               
      Clear Cell Focus                                 8 (16%)     16 (32%)     16 (32%)      4 (8%)                                
      Congestion                                       1 (2%)                    1 (2%)                                             
      Cyst                                                                                    1 (2%)                                
      Degeneration, Cystic                             3 (6%)       7 (14%)      5 (10%)      6 (12%)                               
      Eosinophilic Focus                              10 (20%)      8 (16%)      9 (18%)      7 (14%)                               
      Fatty Change                                    23 (46%)     18 (36%)     21 (42%)      9 (18%)                               
      Hematopoietic Cell Proliferation                                                        1 (2%)                                
      Hepatodiaphragmatic Nodule                       8 (16%)      5 (10%)      9 (18%)      6 (12%)                               
      Inclusion Body Intracytoplasmic                                                         1 (2%)                                
      Inflammation, Chronic Active                    16 (32%)     21 (42%)     29 (58%)     10 (20%)                               
      Mixed Cell Focus                                16 (32%)     23 (46%)     22 (44%)     10 (20%)                               
      Necrosis                                         4 (8%)       1 (2%)                    3 (6%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Thrombosis                                                    1 (2%)                                                          
      Vacuolization Cytoplasmic                       14 (28%)     18 (36%)     23 (46%)     28 (57%)                               
      Bile Duct, Fibrosis                              1 (2%)                                                                       
      Bile Duct, Hyperplasia                          42 (84%)     48 (96%)     48 (96%)     36 (73%)                               
   Mesentery                                          (13)         (13)         (11)         (12)                                   
      Artery, Inflammation, Chronic Active             1 (8%)                                                                       
      Fat, Inflammation, Chronic Active                8 (62%)     12 (92%)     11 (100%)     9 (75%)                               
      Fat, Mineralization                                           1 (8%)                                                          
      Fat, Necrosis                                    1 (8%)       1 (8%)                    1 (8%)                                
   Pancreas                                           (50)         (49)         (50)         (50)                                   
      Cytoplasmic Alteration                           2 (4%)                    3 (6%)                                             
      Fibrosis                                                      1 (2%)                                                          
      Hyperplasia                                      4 (8%)      10 (20%)     11 (22%)     12 (24%)                               
      Acinus, Atrophy                                 10 (20%)     13 (27%)     12 (24%)     14 (28%)                               
      Artery, Inflammation, Chronic Active             1 (2%)                    1 (2%)                                             
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Erosion                                          1 (2%)                                                                       
      Hyperkeratosis                                   1 (2%)                                                                       
      Hyperplasia                                      3 (6%)       3 (6%)                    1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       1 (2%)                                                          
      Perforation                                      1 (2%)                                                                       
      Ulcer                                            2 (4%)       2 (4%)       2 (4%)                                             
      Epithelium, Hyperplasia                                                    1 (2%)                                             
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
      Erosion                                          3 (6%)                    5 (10%)      2 (4%)                                
      Mineralization                                   1 (2%)                                                                       
      Ulcer                                            4 (8%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (50)         (49)         (50)         (50)                                   
      Inflammation, Chronic Active                     1 (2%)       1 (2%)                                                          
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  43 (86%)     48 (96%)     41 (82%)     46 (92%)                               
      Fibrosis                                         1 (2%)                    1 (2%)                                             
      Thrombosis                                       3 (6%)       1 (2%)       1 (2%)       3 (6%)                                
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
      Endocardium, Hyperplasia                                                                1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Angiectasis                                      5 (10%)      3 (6%)      12 (24%)      9 (18%)                               
      Atrophy                                          1 (2%)                    1 (2%)                                             
      Degeneration, Cystic                                                       1 (2%)                                             

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hematopoietic Cell Proliferation                                                        2 (4%)                                
      Hyperplasia                                      9 (18%)     10 (20%)     11 (22%)      8 (16%)                               
      Necrosis                                                                   1 (2%)                                             
      Pigmentation                                                               1 (2%)                                             
      Thrombosis                                                                 1 (2%)                                             
      Vacuolization Cytoplasmic                        8 (16%)      3 (6%)       3 (6%)       5 (10%)                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                     11 (22%)      5 (10%)      7 (14%)      7 (14%)                               
      Mineralization                                                1 (2%)                                                          
   Islets, Pancreatic                                 (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       1 (2%)                    1 (2%)                                
   Parathyroid Gland                                  (46)         (46)         (50)         (50)                                   
      Fibrosis                                                      1 (2%)                                                          
      Hyperplasia, Focal                                                         1 (2%)                                             
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)                    3 (6%)                                             
      Atrophy                                          1 (2%)                    1 (2%)                                             
      Cyst                                             5 (10%)      5 (10%)      7 (14%)      1 (2%)                                
      Hyperplasia                                     13 (26%)     17 (34%)     16 (32%)     10 (20%)                               
      Craniopharyngeal Duct, Hyperplasia                            1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      C-Cell, Hyperplasia                             23 (46%)     29 (58%)     35 (70%)     29 (58%)                               
      Follicle, Cyst                                   1 (2%)                                                                       
      Follicular Cell, Hyperplasia                     3 (6%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     1 (2%)                    1 (2%)                                             
   Preputial Gland                                    (50)         (50)         (50)         (49)                                   
      Hyperplasia                                      1 (2%)       1 (2%)       1 (2%)                                             
      Inflammation, Chronic Active                    41 (82%)     45 (90%)     46 (92%)     45 (92%)                               
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Atrophy                                                       1 (2%)       1 (2%)       3 (6%)                                
      Cyst                                             1 (2%)                                                                       
      Hyperplasia                                                                5 (10%)      2 (4%)                                
      Inflammation                                    25 (50%)     25 (50%)     17 (34%)     24 (48%)                               
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)       2 (4%)       1 (2%)       4 (8%)                                
      Inflammation, Chronic Active                     1 (2%)                                                                       
   Testes                                             (50)         (50)         (50)         (50)                                   

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Atrophy                                          6 (12%)      6 (12%)      5 (10%)      2 (4%)                                
      Mineralization                                   1 (2%)                                                                       
      Necrosis                                                                   1 (2%)                                             
      Interstitial Cell, Hyperplasia                   9 (18%)      6 (12%)      4 (8%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia                                     17 (34%)     14 (28%)     19 (38%)     20 (40%)                               
      Myelofibrosis                                    1 (2%)                                                                       
   Lymph Node                                         (7)          (3)          (3)          (4)                                    
      Mediastinal, Congestion                          1 (14%)                                                                      
      Mediastinal, Ectasia                                                       1 (33%)                                            
      Mediastinal, Inflammation, Chronic Active                                  1 (33%)                                            
      Renal, Congestion                                                          1 (33%)                                            
      Renal, Ectasia                                                1 (33%)                                                         
      Renal, Inflammation, Chronic Active                                        1 (33%)                                            
   Lymph Node, Mandibular                             (49)         (50)         (49)         (49)                                   
      Ectasia                                          1 (2%)       4 (8%)       1 (2%)       4 (8%)                                
      Hyperplasia                                      1 (2%)                                                                       
      Hyperplasia, Plasma Cell                         2 (4%)       1 (2%)                    2 (4%)                                
   Lymph Node, Mesenteric                             (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)                                                                       
      Ectasia                                          2 (4%)       3 (6%)       1 (2%)       4 (8%)                                
      Inflammation, Chronic Active                                               2 (4%)                                             
   Spleen                                             (50)         (50)         (50)         (49)                                   
      Accessory Spleen                                                           1 (2%)                                             
      Angiectasis                                                   1 (2%)                                                          
      Fibrosis                                         6 (12%)      4 (8%)       4 (8%)       4 (8%)                                
      Hematopoietic Cell Proliferation                 4 (8%)       3 (6%)       3 (6%)       7 (14%)                               
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia, Histiocytic                                                                1 (2%)                                
      Necrosis                                         1 (2%)                    1 (2%)       1 (2%)                                
      Capsule, Fibrosis                                             1 (2%)                                                          
      Capsule, Inflammation, Chronic Active                                                   1 (2%)                                
   Thymus                                             (49)         (47)         (45)         (50)                                   
      Cyst                                             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (46)         (50)         (49)         (49)                                   
      Galactocele                                                   5 (10%)                   1 (2%)                                
      Hyperplasia                                      2 (4%)       3 (6%)       4 (8%)       4 (8%)                                
   Skin                                               (49)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 (2%)                                                                       

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Hyperkeratosis                                                             2 (4%)       1 (2%)                                
      Hyperplasia                                                                2 (4%)                                             
      Inflammation, Chronic Active                                               1 (2%)       1 (2%)                                
      Parakeratosis                                                              1 (2%)                                             
      Subcutaneous Tissue, Fibrosis                                              1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Chronic                                                                                    
          Active                                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hydrocephalus                                                                           1 (2%)                                
      Necrosis                                         2 (4%)                    1 (2%)                                             
      Artery, Inflammation, Chronic Active             1 (2%)                                                                       
   Spinal Cord                                        (1)          (2)          (1)          (1)                                    
      Hemorrhage                                                                              1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)                                                          
      Congestion                                                    2 (4%)       1 (2%)                                             
      Edema                                                         1 (2%)                                                          
      Hemorrhage                                       4 (8%)                    2 (4%)                                             
      Inflammation, Chronic Active                     3 (6%)       3 (6%)       4 (8%)       6 (12%)                               
      Leukocytosis                                                               1 (2%)                                             
      Alveolar Epithelium, Hyperplasia                 3 (6%)       8 (16%)      6 (12%)      4 (8%)                                
   Nose                                               (50)         (50)         (49)         (50)                                   
      Abscess                                                                                 1 (2%)                                
      Inflammation, Chronic Active                     6 (12%)      7 (14%)      6 (12%)      6 (12%)                               
      Thrombosis                                       2 (4%)       1 (2%)                    1 (2%)                                
      Olfactory Epithelium, Atrophy                                                          48 (96%)                               
      Olfactory Epithelium, Metaplasia                                                       47 (94%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 88050-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         METHACRYLONITRILE                                     Date: 02/24/00  
Route: GAVAGE                                                                                                     Time: 14:18:49  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     0 MG/KG      3 MG/KG      10 MG/KG     30 MG/KG                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (1)                                                              
      Cataract                                                      1 (100%)                                                        
      Degeneration                                     1 (100%)                                                                     
      Lens, Mineralization                                          1 (100%)                                                        
      Retina, Atrophy                                               1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                                          2 (4%)       1 (2%)                                             
      Fibrosis                                                                   1 (2%)                                             
      Infarct                                          1 (2%)                    1 (2%)                                             
      Inflammation, Chronic Active                    13 (26%)     25 (50%)     22 (44%)     18 (36%)                               
      Mineralization                                                                          1 (2%)                                
      Nephropathy                                     44 (88%)     48 (96%)     46 (92%)     47 (94%)                               
      Pigmentation                                                  2 (4%)       3 (6%)       1 (2%)                                
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)       1 (2%)                                                          
      Inflammation, Chronic Active                                  1 (2%)                                                          
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
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