National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/9108

TDMS Study 92012-05 Pathology Tables

NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03
Route: DOSED FEED                                                                                                 Time: 10:29:56

                                                      FINAL#1; REVISION #1




       Facility:  Southern Research Institute

       Chemical CAS #:  693-98-1

       Lock Date:  10/16/01

       Cage Range:  All

       Reasons For Removal:    25019 Moribund Sacrifice                25020 Natural Death
                               25021 Terminal Sacrifice

       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: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Natural Death                                      4            3           10            1                                     
    Moribund Sacrifice                                 6            8           12            7                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                40           39           28           41                                     
    Natural Death                                                                             1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (48)         (47)         (44)         (50)                                   
      Edema                                                                                   1 (2%)                                
   Intestine Small, Jejunum                           (47)         (46)         (44)         (49)                                   
      Necrosis, Focal                                                                         1 (2%)                                
   Liver                                              (50)         (49)         (50)         (50)                                   
      Angiectasis, Focal                               2 (4%)       1 (2%)       2 (4%)                                             
      Basophilic Focus                                42 (84%)     44 (90%)     43 (86%)     39 (78%)                               
      Cholangiofibrosis                                                                       1 (2%)                                
      Congestion                                                                 2 (4%)       1 (2%)                                
      Congestion, Focal                                                          1 (2%)                                             
      Degeneration, Cystic, Focal                                   1 (2%)                    2 (4%)                                
      Eosinophilic Focus                                                         1 (2%)                                             
      Fatty Change                                                  2 (4%)       1 (2%)                                             
      Hemorrhage                                       2 (4%)                                 2 (4%)                                
      Hepatodiaphragmatic Nodule                       6 (12%)     11 (22%)     14 (28%)     13 (26%)                               
      Hyperplasia, Focal, Lymphoid                                               1 (2%)       1 (2%)                                
      Infarct                                                                                 2 (4%)                                
      Infiltration Cellular, Mixed Cell               42 (84%)     44 (90%)     34 (68%)     38 (76%)                               
      Inflammation, Granulomatous                     18 (36%)     23 (47%)     22 (44%)     42 (84%)                               
      Mixed Cell Focus                                15 (30%)     14 (29%)     11 (22%)     26 (52%)                               
      Necrosis, Focal                                               1 (2%)                    1 (2%)                                
      Bile Duct, Cholangiofibrosis, Focal                                        1 (2%)                                             
      Bile Duct, Cyst                                  2 (4%)                                                                       
      Bile Duct, Cyst, Multiple                                                  1 (2%)       1 (2%)                                
      Bile Duct, Hyperplasia                          20 (40%)     29 (59%)     20 (40%)     40 (80%)                               
      Hepatocyte, Necrosis, Focal                                                1 (2%)       2 (4%)                                
      Hepatocyte, Vacuolization Cytoplasmic, Focal     9 (18%)     10 (20%)     11 (22%)      9 (18%)                               
      Hepatocyte, Periportal, Vacuolization                                                                                         
        Cytoplasmic                                                              1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatocyte, Centrilobular, Necrosis                                        1 (2%)       1 (2%)                                
      Hepatocyte, Centrilobular, Vacuolization                                                                                      
        Cytoplasmic                                    1 (2%)                    4 (8%)       1 (2%)                                
   Mesentery                                          (8)          (10)         (12)         (9)                                    
      Fibrosis                                                      1 (10%)                                                         
      Hemorrhage, Focal                                                                       1 (11%)                               
      Infiltration Cellular, Mixed Cell                                          1 (8%)                                             
      Inflammation, Chronic                                         1 (10%)                                                         
      Artery, Inflammation, Chronic, Focal                                                    1 (11%)                               
      Fat, Necrosis                                                 1 (10%)      2 (17%)                                            
      Fat, Necrosis, Focal                             5 (63%)      7 (70%)      6 (50%)      3 (33%)                               
   Pancreas                                           (50)         (49)         (49)         (50)                                   
      Infiltration Cellular, Diffuse, Mixed Cell                    1 (2%)                                                          
      Acinus, Atrophy, Diffuse                         1 (2%)       1 (2%)                    1 (2%)                                
      Acinus, Atrophy, Focal                          13 (26%)     14 (29%)     13 (27%)     11 (22%)                               
      Duct, Cyst, Focal                                1 (2%)                                 1 (2%)                                
      Duct, Cyst, Focal, Multiple                      9 (18%)     12 (24%)      4 (8%)       5 (10%)                               
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
      Duct, Mineralization, Focal                                                             2 (4%)                                
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                     1 (2%)       1 (2%)                    2 (4%)                                
      Edema                                                                                   1 (2%)                                
      Erosion                                                                    1 (2%)                                             
      Inflammation, Chronic                                         1 (2%)       1 (2%)                                             
      Inflammation, Focal                                                        1 (2%)                                             
      Ulcer                                                         2 (4%)       1 (2%)       1 (2%)                                
      Epithelium, Hyperplasia                          3 (6%)       1 (2%)       4 (8%)       1 (2%)                                
   Stomach, Glandular                                 (49)         (49)         (48)         (50)                                   
      Erosion                                                       1 (2%)       1 (2%)                                             
      Inflammation, Chronic                                                      1 (2%)                                             
      Necrosis, Focal                                                            1 (2%)                                             
      Ulcer                                            1 (2%)                                                                       
      Epithelium, Hyperplasia, Focal                   1 (2%)                                                                       
      Glands, Degeneration, Cystic, Focal                                        1 (2%)                                             
      Glands, Ectasia, Focal                           1 (2%)                                                                       
      Glands, Hyperplasia, Focal                                                              2 (4%)                                
   Tongue                                             (3)                       (1)                                                 
      Epithelium, Hyperplasia, Focal                   1 (33%)                                                                      
   Tooth                                              (1)                                                                           
      Peridontal Tissue, Inflammation, Chronic         1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                   5 (10%)      8 (16%)      7 (14%)      6 (12%)                               
      Infiltration Cellular, Mixed Cell                             4 (8%)       3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                2 (4%)       2 (4%)       5 (10%)      5 (10%)                               
      Angiectasis                                      1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Cytoplasmic Alteration, Focal                    3 (6%)                    1 (2%)       5 (10%)                               
      Hematopoietic Cell Proliferation                              1 (2%)                                                          
      Hemorrhage                                                    1 (2%)                                                          
      Hemorrhage, Focal                                             1 (2%)                                                          
      Vacuolization Cytoplasmic, Focal                 8 (16%)      3 (6%)       7 (14%)     12 (24%)                               
   Adrenal Medulla                                    (49)         (49)         (50)         (50)                                   
      Hyperplasia, Focal                               1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
   Pituitary Gland                                    (50)         (48)         (50)         (50)                                   
      Angiectasis                                      5 (10%)      9 (19%)      7 (14%)      2 (4%)                                
      Cyst                                                          1 (2%)                                                          
      Hemorrhage                                                    1 (2%)                                                          
      Metaplasia, Focal, Lipocyte                                                1 (2%)                                             
      Pars Distalis, Angiectasis                                                              1 (2%)                                
      Pars Distalis, Cyst                              1 (2%)       3 (6%)       2 (4%)       1 (2%)                                
      Pars Distalis, Cyst, Multiple                                 2 (4%)                                                          
      Pars Distalis, Cytoplasmic Alteration, Focal     4 (8%)       4 (8%)       1 (2%)       3 (6%)                                
      Pars Distalis, Degeneration, Cystic              1 (2%)                                                                       
      Pars Distalis, Degeneration, Cystic, Focal       9 (18%)     14 (29%)      8 (16%)      5 (10%)                               
      Pars Distalis, Hemorrhage, Focal                 1 (2%)       3 (6%)       4 (8%)       6 (12%)                               
      Pars Distalis, Hyperplasia, Focal                1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Pars Distalis, Pigmentation, Focal                                         1 (2%)                                             
      Pars Intermedia, Cyst                                                      1 (2%)       3 (6%)                                
      Pars Intermedia, Degeneration, Cystic, Focal                                            1 (2%)                                
      Pars Intermedia, Hemorrhage                                                             1 (2%)                                
      Pars Intermedia, Pars Nervosa, Atypia                                                                                         
        Cellular, Focal                                             1 (2%)                                                          
      Rathke's Cleft, Cyst                             1 (2%)                    1 (2%)                                             
      Rathke's Cleft, Hemorrhage                                                              2 (4%)                                
   Thyroid Gland                                      (49)         (48)         (42)         (48)                                   
      Vacuolization Cytoplasmic, Focal                              1 (2%)                                                          
      C-Cell, Hyperplasia                             48 (98%)     46 (96%)     40 (95%)     25 (52%)                               
      Follicle, Cyst                                                2 (4%)       1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Follicle, Mineralization, Focal                 42 (86%)     47 (98%)     41 (98%)     48 (100%)                              
      Follicular Cell, Hyperplasia                                 41 (85%)     34 (81%)     46 (96%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (3)                       (4)          (2)                                    
      Mediastinum, Infiltration Cellular, Mixed                                                                                     
        Cell                                                                     1 (25%)                                            
      Pelvic, Hemorrhage, Focal                                                               1 (50%)                               
      Thoracic, Infiltration Cellular, Focal,                                                                                       
        Mixed Cell                                                               1 (25%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (49)         (50)         (50)                                   
      Degeneration, Cystic                             6 (12%)      4 (8%)       1 (2%)       1 (2%)                                
      Fibrosis, Focal                                               1 (2%)                                                          
      Hyperplasia, Cystic                              1 (2%)       4 (8%)       3 (6%)       1 (2%)                                
      Inflammation, Chronic                            2 (4%)       5 (10%)      4 (8%)                                             
   Ovary                                              (50)         (49)         (50)         (50)                                   
      Angiectasis                                      1 (2%)       1 (2%)                                                          
      Atrophy                                                       1 (2%)                                                          
      Congestion                                                                 1 (2%)                                             
      Cyst                                             5 (10%)      5 (10%)      1 (2%)                                             
      Bilateral, Cyst, Multiple                                                  1 (2%)                                             
      Periovarian Tissue, Cyst                         4 (8%)       5 (10%)      4 (8%)       6 (12%)                               
      Periovarian Tissue, Cyst, Multiple               1 (2%)                                                                       
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             3 (6%)                    1 (2%)       1 (2%)                                
      Hemorrhage                                                                 2 (4%)                                             
      Inflammation, Chronic                                                      1 (2%)                                             
      Cervix, Hyperplasia                                                        1 (2%)                                             
      Endometrium, Hyperplasia, Cystic                10 (20%)     14 (28%)     15 (30%)     15 (30%)                               
   Vagina                                             (2)                       (2)                                                 
      Inflammation, Chronic                                                      1 (50%)                                            
      Epithelium, Cyst                                 1 (50%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Atrophy                                          1 (2%)                                                                       
      Fibrosis                                                                                1 (2%)                                
      Hyperplasia, Focal, Histiocytic                               1 (2%)                    4 (8%)                                
      Myelofibrosis                                                                           1 (2%)                                
      Necrosis                                                                                1 (2%)                                
      Myeloid Cell, Hyperplasia                        2 (4%)       3 (6%)       5 (10%)      2 (4%)                                
      Myeloid Cell, Erythroid Cell, Hyperplasia                     2 (4%)       1 (2%)                                             
   Lymph Node                                         (32)         (31)         (34)         (41)                                   
      Deep Cervical, Hemorrhage                                                               2 (5%)                                
      Mediastinal, Angiectasis                         1 (3%)                                                                       
      Mediastinal, Congestion                                                    1 (3%)                                             
      Mediastinal, Ectasia                             5 (16%)      3 (10%)      2 (6%)       7 (17%)                               
      Mediastinal, Hemorrhage                          2 (6%)       3 (10%)      9 (26%)      8 (20%)                               
      Mediastinal, Hyperplasia                                      1 (3%)       2 (6%)                                             
      Mediastinal, Hyperplasia, Histiocytic            8 (25%)      8 (26%)      5 (15%)     12 (29%)                               
      Mediastinal, Hyperplasia, Lymphoid                            1 (3%)       1 (3%)       1 (2%)                                
      Mediastinal, Pigmentation                        1 (3%)                    2 (6%)                                             
      Pancreatic, Atrophy                                           1 (3%)                                                          
      Pancreatic, Ectasia                              2 (6%)       2 (6%)                   11 (27%)                               
      Pancreatic, Hemorrhage                           5 (16%)      3 (10%)      2 (6%)       9 (22%)                               
      Pancreatic, Hyperplasia, Histiocytic            16 (50%)     24 (77%)     17 (50%)     18 (44%)                               
      Pancreatic, Hyperplasia, Plasma Cell             1 (3%)                                                                       
      Pancreatic, Infiltration Cellular, Mixed Cell                                           1 (2%)                                
      Pancreatic, Pigmentation                         4 (13%)      2 (6%)                    1 (2%)                                
   Lymph Node, Mandibular                             (5)          (4)          (5)          (1)                                    
      Ectasia                                          1 (20%)                                                                      
   Lymph Node, Mesenteric                             (49)         (49)         (49)         (50)                                   
      Angiectasis                                                                1 (2%)                                             
      Ectasia                                          1 (2%)                                 5 (10%)                               
      Hemorrhage                                       1 (2%)                    2 (4%)       2 (4%)                                
      Hyperplasia, Histiocytic                         2 (4%)       1 (2%)       2 (4%)       2 (4%)                                
      Hyperplasia, Lymphoid                                         1 (2%)                                                          
      Pigmentation                                     2 (4%)                                                                       
   Spleen                                             (50)         (49)         (48)         (50)                                   
      Accessory Spleen                                              1 (2%)       1 (2%)                                             
      Angiectasis, Focal                                            1 (2%)                                                          
      Congestion                                                    1 (2%)                                                          
      Fibrosis, Focal                                               1 (2%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                 6 (12%)      8 (16%)      5 (10%)      4 (8%)                                
      Hemorrhage                                                                 1 (2%)                                             
      Infarct                                                                                 1 (2%)                                
      Inflammation, Granulomatous                      3 (6%)       2 (4%)       4 (8%)      27 (54%)                               
      Pigmentation                                                  1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pigmentation, Focal                              1 (2%)       1 (2%)       1 (2%)                                             
   Thymus                                             (48)         (45)         (49)         (49)                                   
      Angiectasis                                                                2 (4%)                                             
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                    2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Dilatation                                      33 (66%)     35 (70%)     22 (44%)     19 (38%)                               
      Ectasia                                          2 (4%)       3 (6%)       7 (14%)                                            
      Fibrosis                                                      1 (2%)                                                          
      Hyperplasia                                      3 (6%)       5 (10%)      4 (8%)       3 (6%)                                
      Hyperplasia, Cystic                              1 (2%)                    2 (4%)                                             
      Inflammation, Focal                                           1 (2%)                                                          
   Skin                                               (50)         (50)         (50)         (50)                                   
      Necrosis, Focal                                                                         4 (8%)                                
      Ulcer                                                                      1 (2%)       1 (2%)                                
      Subcutaneous Tissue, Angiectasis, Focal                                                 1 (2%)                                
      Subcutaneous Tissue, Hemorrhage, Focal                                                  1 (2%)                                
      Subcutaneous Tissue, Inflammation, Focal,                                                                                     
         Suppurative                                                                          1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (50)         (50)                                   
      Compression, Focal                              10 (20%)      8 (16%)     12 (24%)      4 (8%)                                
      Hemorrhage, Focal                                2 (4%)       1 (2%)       2 (4%)                                             
      Necrosis, Focal                                                            2 (4%)                                             
      Pigmentation, Focal                                                        1 (2%)                                             
      Cerebellum, Developmental Malformation                                     1 (2%)                                             
   Spinal Cord                                        (3)          (1)          (4)                                                 
      Hemorrhage, Focal                                1 (33%)                                                                      
      Necrosis, Focal                                  1 (33%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (49)         (50)         (50)                                   
      Congestion                                       2 (4%)       4 (8%)       2 (4%)       2 (4%)                                
      Emphysema                                                                  1 (2%)                                             
      Hemorrhage                                       1 (2%)                                                                       
      Hemorrhage, Focal                                1 (2%)                                 2 (4%)                                
      Hyperplasia, Focal, Histiocytic                                            1 (2%)       1 (2%)                                
      Hyperplasia, Histiocytic                         6 (12%)      6 (12%)      7 (14%)      1 (2%)                                
      Infiltration Cellular, Focal, Mixed Cell                                                1 (2%)                                
      Infiltration Cellular, Mixed Cell                             3 (6%)       1 (2%)       6 (12%)                               
      Inflammation, Chronic, Focal                     1 (2%)       2 (4%)       1 (2%)                                             
      Inflammation, Focal, Granulomatous               1 (2%)                                 1 (2%)                                
      Pigmentation, Focal                              1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia, Focal          7 (14%)      5 (10%)      3 (6%)       3 (6%)                                
      Alveolus, Inflammation, Focal, Granulomatous                                            1 (2%)                                
      Interstitium, Edema                                                        1 (2%)                                             
   Nose                                               (50)         (49)         (50)         (50)                                   
      Foreign Body                                                  1 (2%)                    1 (2%)                                
      Inflammation, Suppurative                        1 (2%)       1 (2%)                    2 (4%)                                
      Nasolacrimal Duct, Inflammation                  4 (8%)       2 (4%)       4 (8%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (49)         (49)         (50)                                   
      Atrophy                                          1 (2%)       1 (2%)       1 (2%)                                             
      Cataract                                         1 (2%)       2 (4%)       2 (4%)       1 (2%)                                
      Iris, Synechia                                                             1 (2%)                                             
      Retina, Degeneration                                          2 (4%)       1 (2%)       1 (2%)                                
   Harderian Gland                                    (50)         (49)         (50)         (50)                                   
      Hyperplasia, Cystic, Focal                       1 (2%)                                                                       
      Hyperplasia, Focal                               2 (4%)                    1 (2%)       1 (2%)                                
      Hyperplasia, Focal, Histiocytic                  1 (2%)       2 (4%)       1 (2%)       4 (8%)                                
      Inflammation, Chronic, Focal                                               3 (6%)       1 (2%)                                
      Inflammation, Focal, Granulomatous                                         1 (2%)                                             
      Epithelium, Hyperplasia, Focal                                2 (4%)       2 (4%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (48)         (47)         (50)                                   
      Atrophy, Focal                                                2 (4%)       1 (2%)                                             
      Congestion                                                                 2 (4%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   0PPM         1000 PPM     2500 PPM     5000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Cyst                                                                                    1 (2%)                                
      Infarct                                                                    1 (2%)                                             
      Nephropathy                                     38 (76%)     40 (83%)     38 (81%)     40 (80%)                               
      Glomerulus, Amyloid Deposition, Diffuse                                                 1 (2%)                                
      Pelvis, Inflammation                                                       1 (2%)                                             
      Renal Tubule, Accumulation, Hyaline Droplet     11 (22%)      7 (15%)      3 (6%)       4 (8%)                                
      Renal Tubule, Pigmentation                       8 (16%)      4 (8%)       5 (11%)                                            
   Urethra                                                                                   (2)                                    
      Transitional Epithelium, Hyperplasia, Diffuse                                           1 (50%)                               
   Urinary Bladder                                    (50)         (49)         (49)         (50)                                   
      Transitional Epithelium, Hyperplasia                                                    2 (4%)                                
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                13            6            7           13                                     
    Natural Death                                      2            4            7            2                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                34           39           35           35                                     
    Moribund Sacrifice                                 1                                                                            
    Natural Death                                                   1            1                                                  
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Rectum                            (49)         (48)         (48)         (50)                                   
      Angiectasis, Focal                                                         1 (2%)                                             
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis, Focal                                                         1 (2%)                                             
      Basophilic Focus                                23 (46%)     23 (46%)      8 (16%)      2 (4%)                                
      Cholangiofibrosis                                1 (2%)                                 1 (2%)                                
      Congestion                                                                 2 (4%)       1 (2%)                                
      Degeneration, Cystic, Focal                      4 (8%)       3 (6%)       2 (4%)       7 (14%)                               
      Eosinophilic Focus                               3 (6%)                    6 (12%)      1 (2%)                                
      Fibrosis, Focal                                                            1 (2%)                                             
      Hematopoietic Cell Proliferation                                                        2 (4%)                                
      Hepatodiaphragmatic Nodule                       6 (12%)      5 (10%)      4 (8%)       9 (18%)                               
      Hyperplasia, Focal, Lymphoid                     1 (2%)                    2 (4%)       1 (2%)                                
      Infiltration Cellular, Mixed Cell               25 (50%)     30 (60%)     27 (54%)     36 (72%)                               
      Inflammation, Granulomatous                     12 (24%)     11 (22%)      4 (8%)      11 (22%)                               
      Mixed Cell Focus                                14 (28%)     16 (32%)     23 (46%)     26 (52%)                               
      Necrosis, Focal                                  2 (4%)                    2 (4%)       1 (2%)                                
      Pigmentation, Focal                                                        2 (4%)                                             
      Bile Duct, Cyst                                                                         1 (2%)                                
      Bile Duct, Hyperplasia                          49 (98%)     49 (98%)     47 (94%)     49 (98%)                               
      Centrilobular, Congestion                                                  1 (2%)                                             
      Hepatocyte, Necrosis, Focal                      1 (2%)       1 (2%)       3 (6%)       2 (4%)                                
      Hepatocyte, Vacuolization Cytoplasmic,                                                                                        
        Diffuse                                                     1 (2%)                    1 (2%)                                
      Hepatocyte, Vacuolization Cytoplasmic, Focal    23 (46%)     30 (60%)     26 (52%)     23 (46%)                               
      Hepatocyte, Centrilobular, Necrosis                           2 (4%)       2 (4%)                                             
      Hepatocyte, Centrilobular, Vacuolization                                                                                      
        Cytoplasmic                                    5 (10%)      4 (8%)                    3 (6%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatocyte, Midzonal, Vacuolization                                                                                           
        Cytoplasmic                                    1 (2%)       1 (2%)       2 (4%)                                             
      Oval Cell, Hyperplasia                                                                  1 (2%)                                
      Serosa, Fibrosis, Focal                                       2 (4%)                                                          
   Mesentery                                          (26)         (46)         (35)         (20)                                   
      Fibrosis, Focal                                                                         1 (5%)                                
      Hemorrhage                                                                              2 (10%)                               
      Necrosis, Focal                                                                         1 (5%)                                
      Artery, Inflammation, Chronic                                                           1 (5%)                                
      Fat, Necrosis                                    1 (4%)       1 (2%)       2 (6%)                                             
      Fat, Necrosis, Focal                             8 (31%)     10 (22%)     16 (46%)     10 (50%)                               
   Pancreas                                           (49)         (49)         (50)         (50)                                   
      Atrophy, Diffuse                                                           1 (2%)                                             
      Atrophy, Focal                                                             1 (2%)       1 (2%)                                
      Fibrosis, Focal                                                                         1 (2%)                                
      Acinus, Atrophy, Diffuse                                      1 (2%)                    1 (2%)                                
      Acinus, Atrophy, Focal                          22 (45%)     27 (55%)     20 (40%)     36 (72%)                               
      Acinus, Hyperplasia, Focal                                                 1 (2%)                                             
      Duct, Cyst                                       1 (2%)                                                                       
      Duct, Cyst, Focal                                             1 (2%)                                                          
      Duct, Cyst, Focal, Multiple                      6 (12%)      2 (4%)       5 (10%)     12 (24%)                               
      Duct, Hyperplasia, Cystic                                     1 (2%)       1 (2%)                                             
      Duct, Hyperplasia, Cystic, Focal                              2 (4%)       3 (6%)                                             
      Duct, Hyperplasia, Focal                                      1 (2%)                                                          
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy, Focal                                                                          1 (2%)                                
      Inflammation, Chronic                                                                   1 (2%)                                
   Stomach, Forestomach                               (50)         (50)         (50)         (49)                                   
      Diverticulum                                     1 (2%)       1 (2%)       2 (4%)       1 (2%)                                
      Edema                                            1 (2%)                                                                       
      Erosion                                                       1 (2%)                    1 (2%)                                
      Inflammation, Focal                              1 (2%)                                 1 (2%)                                
      Ulcer                                            2 (4%)       1 (2%)       1 (2%)       4 (8%)                                
      Epithelium, Hyperplasia                          2 (4%)       3 (6%)                    6 (12%)                               
      Epithelium, Hyperplasia, Focal                                                          1 (2%)                                
      Serosa, Foreign Body                                                                    1 (2%)                                
      Serosa, Inflammation, Chronic, Focal                                                    1 (2%)                                
   Stomach, Glandular                                 (50)         (50)         (50)         (49)                                   
      Erosion                                          4 (8%)       1 (2%)       1 (2%)                                             
      Erosion, Focal                                   1 (2%)                    1 (2%)                                             
      Inflammation, Focal                              1 (2%)                                                                       
      Ulcer                                            2 (4%)                                                                       
      Epithelium, Necrosis, Focal                                                             1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Glands, Hyperplasia, Cystic, Focal                            1 (2%)                                                          
      Glands, Hyperplasia, Focal                       1 (2%)                                                                       
   Tongue                                             (1)          (2)                       (1)                                    
      Epithelium, Hyperplasia, Focal                                                          1 (100%)                              
   Tooth                                              (1)          (1)          (1)          (2)                                    
      Malformation                                                  1 (100%)                                                        
      Peridontal Tissue, Inflammation                  1 (100%)                                                                     
      Peridontal Tissue, Inflammation, Chronic                                                1 (50%)                               
      Peridontal Tissue, Inflammation, Focal,                                                                                       
        Suppurative                                                              1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   3 (6%)       5 (10%)     10 (20%)      5 (10%)                               
      Cardiomyopathy, Focal                                                      2 (4%)       1 (2%)                                
      Congestion                                                                 1 (2%)                                             
      Fibrosis                                                                                1 (2%)                                
      Infiltration Cellular, Mixed Cell                             1 (2%)                                                          
      Thrombosis                                       1 (2%)       1 (2%)                                                          
      Endocardium, Myocardium, Fibrosis, Focal         1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                1 (2%)       4 (8%)       9 (18%)      5 (10%)                               
      Cytoplasmic Alteration, Focal                    2 (4%)       1 (2%)       1 (2%)       3 (6%)                                
      Degeneration, Cystic, Focal                                                1 (2%)                                             
      Hemorrhage                                       2 (4%)                                                                       
      Vacuolization Cytoplasmic, Focal                 6 (12%)      9 (18%)     10 (20%)     10 (20%)                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)                                                          
      Hyperplasia                                      1 (2%)       1 (2%)                    1 (2%)                                
      Hyperplasia, Focal                               7 (14%)      5 (10%)      3 (6%)       7 (14%)                               
      Infiltration Cellular, Lymphoid                               1 (2%)                                                          
      Vacuolization Cytoplasmic, Focal                              1 (2%)                                                          
   Islets, Pancreatic                                 (50)         (49)         (50)         (50)                                   
      Atrophy                                                       1 (2%)                                                          
      Hyperplasia, Focal                                            2 (4%)       1 (2%)       1 (2%)                                
   Parathyroid Gland                                  (47)         (49)         (48)         (49)                                   
      Cyst                                                          1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   12                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hyperplasia                                                                             1 (2%)                                
      Hyperplasia, Focal                               1 (2%)                    1 (2%)                                             
      Bilateral, Hyperplasia, Focal                    1 (2%)                                                                       
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)                    3 (6%)                                             
      Pars Distalis, Angiectasis                       3 (6%)       2 (4%)       2 (4%)       1 (2%)                                
      Pars Distalis, Cyst                              1 (2%)       4 (8%)       2 (4%)       3 (6%)                                
      Pars Distalis, Cytoplasmic Alteration, Focal     1 (2%)       4 (8%)       2 (4%)       5 (10%)                               
      Pars Distalis, Degeneration, Cystic, Focal       1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Pars Distalis, Hyperplasia, Focal                2 (4%)       1 (2%)                    2 (4%)                                
      Pars Distalis, Inflammation, Chronic, Focal,                                                                                  
         Granulomatous                                                           1 (2%)                                             
      Pars Distalis, Pars Intermedia, Angiectasis                   1 (2%)                                                          
      Pars Intermedia, Cyst                                         2 (4%)                    1 (2%)                                
      Pars Intermedia, Hemorrhage                                                1 (2%)                                             
      Pars Intermedia, Hyperplasia, Focal                           1 (2%)                                                          
      Pars Nervosa, Infiltration Cellular, Focal,                                                                                   
         Mixed Cell                                                              1 (2%)                                             
   Thyroid Gland                                      (48)         (46)         (43)         (50)                                   
      Cyst                                                          1 (2%)                                                          
      C-Cell, Hyperplasia                             41 (85%)     43 (93%)     38 (88%)     34 (68%)                               
      Follicle, Cyst                                   1 (2%)                                 1 (2%)                                
      Follicle, Mineralization, Focal                 48 (100%)    45 (98%)     43 (100%)    49 (98%)                               
      Follicular Cell, Atrophy, Focal                  1 (2%)                                                                       
      Follicular Cell, Hyperplasia                                 17 (37%)     37 (86%)     43 (86%)                               
      Follicular Cell, Hyperplasia, Cystic, Focal      1 (2%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (7)          (2)          (6)          (4)                                    
      Mediastinum, Hemorrhage                                                                 1 (25%)                               
      Thoracic, Hemorrhage                                                                    1 (25%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Atrophy                                                       1 (2%)                    1 (2%)                                
      Granuloma Sperm                                               1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic                                         1 (2%)       1 (2%)                                             
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                             1 (2%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   13                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Degeneration, Cystic                                                                    2 (4%)                                
      Hyperplasia                                                                1 (2%)                                             
      Hyperplasia, Cystic                              2 (4%)                    2 (4%)       1 (2%)                                
      Hyperplasia, Focal                               1 (2%)                                                                       
      Inflammation, Chronic                            4 (8%)      10 (20%)     10 (20%)     11 (22%)                               
      Inflammation, Chronic, Focal                                  1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)       1 (2%)       2 (4%)                                
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                                                       
      Hyperplasia, Focal                                            1 (2%)                                                          
      Inflammation, Chronic                           15 (30%)     10 (20%)     17 (34%)     19 (38%)                               
      Epithelium, Degeneration, Focal, Mucoid          1 (2%)                                                                       
      Epithelium, Hyperplasia, Focal                   4 (8%)       2 (4%)                    5 (10%)                               
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          5 (10%)      4 (8%)      13 (26%)     13 (26%)                               
      Mineralization, Focal                            1 (2%)                                                                       
      Bilateral, Atrophy                               2 (4%)       3 (6%)       2 (4%)                                             
      Bilateral, Interstitial Cell, Hyperplasia,                                                                                    
         Focal                                                                                2 (4%)                                
      Germinal Epithelium, Atrophy                     2 (4%)       3 (6%)       1 (2%)       1 (2%)                                
      Interstitial Cell, Hyperplasia                                2 (4%)       1 (2%)       1 (2%)                                
      Interstitial Cell, Hyperplasia, Focal            1 (2%)       4 (8%)       4 (8%)       9 (18%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (47)         (50)                                   
      Fibrosis                                                                   1 (2%)                                             
      Hyperplasia                                                   1 (2%)                                                          
      Hyperplasia, Focal, Histiocytic                               1 (2%)       1 (2%)                                             
      Myeloid Cell, Hyperplasia                                     1 (2%)                    5 (10%)                               
   Lymph Node                                         (39)         (49)         (42)         (38)                                   
      Hemorrhage                                                                              1 (3%)                                
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Mediastinal, Angiectasis                                      1 (2%)                                                          
      Mediastinal, Congestion                                                    1 (2%)                                             
      Mediastinal, Ectasia                             1 (3%)                    3 (7%)       1 (3%)                                
      Mediastinal, Hemorrhage                          1 (3%)       1 (2%)       5 (12%)      1 (3%)                                
      Mediastinal, Hyperplasia, Histiocytic            2 (5%)       1 (2%)                    4 (11%)                               
      Mediastinal, Hyperplasia, Lymphoid               1 (3%)       1 (2%)       1 (2%)       1 (3%)                                
      Mediastinal, Pigmentation                                     1 (2%)                    1 (3%)                                
      Pancreatic, Angiectasis                          1 (3%)                                 1 (3%)                                
      Pancreatic, Ectasia                              1 (3%)       3 (6%)       3 (7%)       2 (5%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   14                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pancreatic, Hemorrhage                           1 (3%)                    1 (2%)       4 (11%)                               
      Pancreatic, Hyperplasia, Focal, Histiocytic      1 (3%)                                                                       
      Pancreatic, Hyperplasia, Histiocytic            13 (33%)     12 (24%)     15 (36%)     19 (50%)                               
      Pancreatic, Hyperplasia, Lymphoid                                          1 (2%)       1 (3%)                                
      Pancreatic, Pigmentation                         1 (3%)                                 1 (3%)                                
   Lymph Node, Mandibular                             (2)          (1)          (2)          (2)                                    
      Hyperplasia, Plasma Cell                                                   1 (50%)                                            
   Lymph Node, Mesenteric                             (47)         (50)         (50)         (50)                                   
      Ectasia                                                       2 (4%)                    2 (4%)                                
      Hemorrhage                                                                 1 (2%)       1 (2%)                                
      Hyperplasia, Histiocytic                         1 (2%)       2 (4%)       1 (2%)       4 (8%)                                
      Hyperplasia, Lymphoid                            2 (4%)       1 (2%)                                                          
   Spleen                                             (49)         (49)         (50)         (50)                                   
      Angiectasis, Focal                               1 (2%)                    1 (2%)                                             
      Congestion                                                                              1 (2%)                                
      Cyst                                                          1 (2%)                                                          
      Fibrosis, Focal                                  2 (4%)                    2 (4%)       1 (2%)                                
      Hematopoietic Cell Proliferation                 4 (8%)       4 (8%)       1 (2%)       6 (12%)                               
      Hemorrhage                                                                 1 (2%)                                             
      Hemorrhage, Focal                                                                       1 (2%)                                
      Hyperplasia, Lymphoid                                         1 (2%)       2 (4%)                                             
      Infarct                                          1 (2%)       1 (2%)                                                          
      Inflammation, Granulomatous                                                2 (4%)       3 (6%)                                
      Necrosis, Focal                                  1 (2%)                    1 (2%)       1 (2%)                                
      Pigmentation                                                               1 (2%)                                             
      Capsule, Fibrosis, Focal                         1 (2%)                                                                       
   Thymus                                             (48)         (48)         (44)         (49)                                   
      Atrophy                                          1 (2%)       1 (2%)                                                          
      Cyst, Multiple                                   1 (2%)                                                                       
      Hemorrhage                                       1 (2%)                                 1 (2%)                                
      Hyperplasia, Lymphoid                            2 (4%)       1 (2%)       1 (2%)                                             
      Epithelial Cell, Cyst, Multiple                               1 (2%)                                                          
      Epithelial Cell, Hyperplasia                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (48)         (47)         (45)         (42)                                   
      Dilatation                                       7 (15%)      1 (2%)       3 (7%)       2 (5%)                                
      Ectasia                                                                    1 (2%)                                             
      Hyperplasia                                      2 (4%)                                                                       
      Hyperplasia, Cystic                                                                     1 (2%)                                
      Epithelium, Pigmentation                                      1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   15                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
   Skin                                               (50)         (50)         (50)         (50)                                   
      Angiectasis, Focal                                            1 (2%)                                                          
      Cyst Epithelial Inclusion                                                  1 (2%)       1 (2%)                                
      Fibrosis, Focal                                  1 (2%)                                                                       
      Hemorrhage, Focal                                1 (2%)                                 1 (2%)                                
      Inflammation, Chronic, Focal                     1 (2%)                    1 (2%)       1 (2%)                                
      Necrosis, Focal                                                                         1 (2%)                                
      Pinna, Necrosis, Focal                           1 (2%)                                                                       
      Subcutaneous Tissue, Angiectasis, Focal                                                 1 (2%)                                
      Subcutaneous Tissue, Cyst                                                               1 (2%)                                
      Subcutaneous Tissue, Foreign Body                                                       1 (2%)                                
      Subcutaneous Tissue, Hemorrhage, Focal                                                  1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (2)          (1)          (1)          (4)                                    
      Fibrosis, Focal                                                                         1 (25%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression, Focal                               4 (8%)       2 (4%)       4 (8%)       1 (2%)                                
      Hemorrhage, Focal                                2 (4%)       3 (6%)       2 (4%)       1 (2%)                                
      Necrosis, Focal                                  1 (2%)       1 (2%)                                                          
   Spinal Cord                                        (1)                       (1)                                                 
      Hemorrhage, Focal                                                          1 (100%)                                           
      Mineralization, Focal                                                      1 (100%)                                           
      Necrosis, Focal                                                            1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                                                       (1)          (1)                                    
      Glands, Hyperplasia, Focal                                                              1 (100%)                              
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)                    1 (2%)       1 (2%)                                
      Hemorrhage, Focal                                1 (2%)                    1 (2%)       1 (2%)                                
      Hyperplasia, Focal, Histiocytic                  4 (8%)       1 (2%)                                                          
      Hyperplasia, Histiocytic                         3 (6%)       3 (6%)       2 (4%)       2 (4%)                                
      Infiltration Cellular, Focal, Mixed Cell                                                1 (2%)                                
      Infiltration Cellular, Mixed Cell                2 (4%)       1 (2%)       1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   16                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Inflammation, Focal                                                                     1 (2%)                                
      Metaplasia, Focal, Osseous                                    2 (4%)       1 (2%)       2 (4%)                                
      Metaplasia, Osseous                                                                     2 (4%)                                
      Alveolar Epithelium, Hyperplasia, Focal          2 (4%)       9 (18%)      6 (12%)      5 (10%)                               
      Alveolus, Foreign Body, Focal                                                           1 (2%)                                
      Interstitium, Edema                                                        1 (2%)       1 (2%)                                
   Nose                                               (50)         (50)         (50)         (50)                                   
      Foreign Body                                     1 (2%)                                                                       
      Inflammation, Suppurative                        2 (4%)                    1 (2%)                                             
      Nasolacrimal Duct, Inflammation                               2 (4%)       1 (2%)       2 (4%)                                
      Nasolacrimal Duct, Inflammation, Chronic                      1 (2%)                                                          
      Nasolacrimal Duct, Inflammation, Suppurative                  3 (6%)                                                          
      Sinus, Foreign Body                                           1 (2%)                                                          
      Sinus, Inflammation, Suppurative                              1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (49)         (50)         (46)         (50)                                   
      Atrophy                                                       1 (2%)                                                          
      Cataract                                         1 (2%)                    1 (2%)                                             
      Synechia                                                                   1 (2%)                                             
      Cornea, Inflammation, Focal                                   1 (2%)                                                          
      Cornea, Necrosis, Focal                                       1 (2%)                                                          
      Iris, Hyperplasia                                1 (2%)                                                                       
      Lens, Cataract                                                1 (2%)                                                          
      Retina, Degeneration                                                       1 (2%)                                             
      Retrobulbar, Inflammation, Focal                              1 (2%)                                                          
   Harderian Gland                                    (50)         (50)         (49)         (50)                                   
      Hyperplasia, Focal                                            1 (2%)                    2 (4%)                                
      Hyperplasia, Focal, Histiocytic                                                         1 (2%)                                
      Hyperplasia, Histiocytic                                                   1 (2%)                                             
      Inflammation, Chronic, Focal                     1 (2%)                    2 (4%)       3 (6%)                                
      Inflammation, Focal, Granulomatous                                                      1 (2%)                                
      Epithelium, Hyperplasia, Focal                   3 (6%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (49)         (49)         (50)                                   
      Accumulation, Hyaline Droplet                    1 (2%)                                                                       
      Atrophy, Focal                                                                          1 (2%)                                
      Congestion                                       1 (2%)       1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   17                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 03/14/03    
Route: DOSED FEED                                                                                                 Time: 10:29:56    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     0PPM         300 PPM      1000 PPM     3000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Cyst                                                          2 (4%)                    2 (4%)                                
      Fibrosis, Focal                                                                         1 (2%)                                
      Infarct                                                       1 (2%)                                                          
      Inflammation                                     1 (2%)                                                                       
      Nephropathy                                     43 (88%)     43 (88%)     41 (84%)     46 (92%)                               
      Pelvis, Inflammation, Chronic                                              1 (2%)                                             
      Pelvis, Transitional Epithelium, Hyperplasia                               1 (2%)                                             
      Renal Tubule, Accumulation, Hyaline Droplet      1 (2%)       1 (2%)       3 (6%)       2 (4%)                                
      Renal Tubule, Necrosis, Focal                    1 (2%)                                                                       
      Renal Tubule, Pigmentation                       5 (10%)      3 (6%)       2 (4%)       3 (6%)                                
   Urinary Bladder                                    (50)         (50)         (49)         (50)                                   
      Hemorrhage                                                                 1 (2%)                                             
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   18                                                              
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.