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https://ntp.niehs.nih.gov/go/3167

TDMS Study 92012-06 Pathology Tables

NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04
Route: DOSED FEED                                                                                                 Time: 09:39:04

                                                   FINAL #1; REVISION #2 MICE




       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
                               25026 Other                             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: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 2            3            4            4                                     
    Natural Death                                      2            3            2            1                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                46           42           42           45                                     
    Moribund Sacrifice                                                           1                                                  
    Natural Death                                                   1                                                               
  Other                                                             1            1                                                  
                                                                                                                                    
  Animals Examined Microscopically                    50           49           49           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (48)         (48)         (50)                                   
      Edema                                            2 (4%)                    2 (4%)       2 (4%)                                
   Intestine Small, Jejunum                           (50)         (46)         (48)         (49)                                   
      Hyperplasia, Lymphoid                                         1 (2%)                    1 (2%)                                
      Peyer's Patch, Infiltration Cellular,                                                                                         
        Polymorphonuclear                                                                     1 (2%)                                
   Intestine Small, Ileum                             (47)         (49)         (47)         (48)                                   
      Hyperplasia, Lymphoid                            1 (2%)                                                                       
      Peyer's Patch, Infiltration Cellular,                                                                                         
        Polymorphonuclear                                                                     1 (2%)                                
   Liver                                              (50)         (49)         (49)         (50)                                   
      Angiectasis                                      1 (2%)                                                                       
      Basophilic Focus                                              4 (8%)       1 (2%)       1 (2%)                                
      Clear Cell Focus                                 1 (2%)                    1 (2%)       4 (8%)                                
      Eosinophilic Focus                                                         1 (2%)                                             
      Hematopoietic Cell Proliferation                 3 (6%)       3 (6%)       5 (10%)      3 (6%)                                
      Hemorrhage                                                    1 (2%)                                                          
      Hepatodiaphragmatic Nodule                                                 1 (2%)       2 (4%)                                
      Hyperplasia, Lymphoid                            3 (6%)       3 (6%)                    6 (12%)                               
      Infarct                                                       1 (2%)                                                          
      Infiltration Cellular, Mixed Cell               13 (26%)      5 (10%)     12 (24%)     10 (20%)                               
      Mixed Cell Focus                                 4 (8%)       1 (2%)       3 (6%)                                             
      Necrosis, Focal                                  5 (10%)      2 (4%)       3 (6%)       4 (8%)                                
      Tension Lipidosis                                                          2 (4%)                                             
      Bile Duct, Hyperplasia                                        1 (2%)                                                          
      Hepatocyte, Vacuolization Cytoplasmic                                      1 (2%)                                             
      Kupffer Cell, Pigmentation                                    2 (4%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Mesentery                                          (3)          (4)          (6)          (6)                                    
      Inflammation, Chronic                            1 (33%)      1 (25%)                                                         
      Fat, Angiectasis                                                           1 (17%)      1 (17%)                               
      Fat, Necrosis                                    2 (67%)      3 (75%)      6 (100%)     6 (100%)                              
   Pancreas                                           (50)         (49)         (48)         (50)                                   
      Atrophy                                          1 (2%)                                                                       
      Cyst                                             1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Acinus, Cytoplasmic Alteration                                             2 (4%)       1 (2%)                                
   Salivary Glands                                    (50)         (49)         (49)         (49)                                   
      Atrophy                                          2 (4%)                                 1 (2%)                                
      Hyperplasia, Lymphoid                                         5 (10%)      3 (6%)       2 (4%)                                
   Stomach, Forestomach                               (50)         (49)         (49)         (50)                                   
      Diverticulum                                     1 (2%)                                 5 (10%)                               
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       2 (4%)                                             
      Epithelium, Hyperplasia                          1 (2%)                    4 (8%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (49)         (50)                                   
      Cardiomyopathy                                                                          2 (4%)                                
      Thrombosis                                                                              1 (2%)                                
      Myocardium, Necrosis                                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (49)         (50)                                   
      Accessory Adrenal Cortical Nodule                7 (14%)      5 (10%)      4 (8%)       6 (12%)                               
      Hyperplasia, Focal                                                                      2 (4%)                                
      Capsule, Hyperplasia                             3 (6%)                                                                       
   Adrenal Medulla                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia                                                                1 (2%)                                             
   Islets, Pancreatic                                 (50)         (48)         (48)         (50)                                   
      Hyperplasia                                      1 (2%)       1 (2%)                    1 (2%)                                
   Parathyroid Gland                                  (48)         (46)         (45)         (48)                                   
      Cyst                                                          1 (2%)       1 (2%)       1 (2%)                                
   Pituitary Gland                                    (50)         (49)         (47)         (49)                                   
      Pars Distalis, Angiectasis                                    3 (6%)       1 (2%)       1 (2%)                                
      Pars Distalis, Cyst                              1 (2%)       3 (6%)       1 (2%)                                             
      Pars Distalis, Hyperplasia, Focal                1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
   Thyroid Gland                                      (49)         (48)         (48)         (50)                                   
      Degeneration, Cystic                            15 (31%)     14 (29%)     12 (25%)      9 (18%)                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Follicle, Cyst                                                             1 (2%)       1 (2%)                                
      Follicular Cell, Hyperplasia                     1 (2%)       1 (2%)       1 (2%)       9 (18%)                               
      Follicular Cell, Hypertrophy                     6 (12%)      3 (6%)      23 (48%)     46 (92%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (48)         (48)         (50)                                   
      Inflammation, Chronic                                                                   1 (2%)                                
   Ovary                                              (50)         (49)         (49)         (48)                                   
      Angiectasis                                     12 (24%)      7 (14%)      8 (16%)      8 (17%)                               
      Cyst                                            10 (20%)     11 (22%)     15 (31%)     10 (21%)                               
      Inflammation, Chronic                            3 (6%)                    2 (4%)                                             
      Thrombosis                                                                              1 (2%)                                
      Corpus Luteum, Hyperplasia                                                              1 (2%)                                
   Uterus                                             (50)         (49)         (49)         (50)                                   
      Angiectasis                                      3 (6%)       2 (4%)       2 (4%)       6 (12%)                               
      Inflammation, Chronic                            6 (12%)      2 (4%)       9 (18%)      4 (8%)                                
      Metaplasia, Squamous                             5 (10%)                   5 (10%)      1 (2%)                                
      Cervix, Cyst Epithelial Inclusion                             1 (2%)                                                          
      Endometrium, Fibrosis                                                                   1 (2%)                                
      Endometrium, Hyperplasia, Cystic                48 (96%)     47 (96%)     46 (94%)     45 (90%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (48)         (50)                                   
      Hyperplasia                                     10 (20%)      5 (10%)     13 (27%)     16 (32%)                               
   Lymph Node                                         (12)         (6)          (8)          (9)                                    
      Bronchial, Hyperplasia, Lymphoid                 1 (8%)                                 2 (22%)                               
      Iliac, Ectasia                                                             1 (13%)                                            
      Iliac, Hematopoietic Cell Proliferation          2 (17%)      1 (17%)      1 (13%)                                            
      Iliac, Hyperplasia, Lymphoid                     5 (42%)      3 (50%)      4 (50%)      2 (22%)                               
      Iliac, Pigmentation                                           1 (17%)                                                         
      Inguinal, Hyperplasia, Lymphoid                                            1 (13%)                                            
      Lumbar, Hyperplasia, Lymphoid                    1 (8%)       1 (17%)      2 (25%)      2 (22%)                               
      Lumbar, Pigmentation                                          1 (17%)                                                         
      Mediastinal, Hyperplasia, Lymphoid               1 (8%)       1 (17%)                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pancreatic, Hyperplasia, Lymphoid                                          1 (13%)                                            
      Renal, Hematopoietic Cell Proliferation          1 (8%)                    1 (13%)                                            
      Renal, Hyperplasia, Lymphoid                     3 (25%)      1 (17%)      2 (25%)                                            
   Lymph Node, Mandibular                             (48)         (48)         (46)         (48)                                   
      Atrophy                                                                    2 (4%)                                             
      Hematopoietic Cell Proliferation                 3 (6%)                                                                       
      Hemorrhage                                                                              1 (2%)                                
      Hyperplasia, Lymphoid                           11 (23%)     12 (25%)     10 (22%)     15 (31%)                               
      Hyperplasia, Plasma Cell                         2 (4%)       1 (2%)       4 (9%)                                             
      Pigmentation                                    24 (50%)     20 (42%)     21 (46%)     21 (44%)                               
   Lymph Node, Mesenteric                             (48)         (48)         (47)         (48)                                   
      Ectasia                                                                                 1 (2%)                                
      Hematopoietic Cell Proliferation                 5 (10%)      3 (6%)                    3 (6%)                                
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Hyperplasia, Lymphoid                            3 (6%)       7 (15%)      4 (9%)       6 (13%)                               
      Hyperplasia, Plasma Cell                                      1 (2%)                                                          
   Spleen                                             (50)         (49)         (49)         (50)                                   
      Angiectasis                                                                1 (2%)                                             
      Atrophy                                                       1 (2%)       1 (2%)                                             
      Congestion                                       2 (4%)                                                                       
      Hematopoietic Cell Proliferation                15 (30%)     20 (41%)     24 (49%)     39 (78%)                               
      Hyperplasia, Plasma Cell                                      1 (2%)                                                          
      Pigmentation                                                  4 (8%)      11 (22%)     34 (68%)                               
      Lymphoid Follicle, Atrophy                       1 (2%)       3 (6%)       5 (10%)      4 (8%)                                
      Lymphoid Follicle, Hyperplasia                  12 (24%)     14 (29%)     13 (27%)     16 (32%)                               
   Thymus                                             (50)         (48)         (48)         (50)                                   
      Atrophy                                          5 (10%)      2 (4%)       7 (15%)      3 (6%)                                
      Hyperplasia, Lymphoid                                                                   4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (49)         (49)         (50)                                   
      Hyperplasia                                                   2 (4%)                    2 (4%)                                
   Skin                                               (50)         (49)         (49)         (50)                                   
      Edema                                                                      1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (49)         (49)         (50)                                   
      Hyperostosis                                     9 (18%)     13 (27%)     10 (20%)     11 (22%)                               
   Skeletal Muscle                                                 (1)          (1)                                                 
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
MUSCULOSKELETAL SYSTEM - CONT                                                                                                       
      Necrosis                                                                   1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (49)         (50)                                   
      Hemorrhage                                                    1 (2%)       1 (2%)                                             
      Inflammation, Chronic Active                                  1 (2%)                                                          
      Vacuolization Cytoplasmic                                                               1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (49)         (49)         (50)                                   
      Edema                                            2 (4%)                                 1 (2%)                                
      Foreign Body                                     2 (4%)       2 (4%)       2 (4%)                                             
      Hemorrhage                                       4 (8%)       3 (6%)       1 (2%)       4 (8%)                                
      Hyperplasia, Lymphoid                            9 (18%)      6 (12%)      3 (6%)       7 (14%)                               
      Infiltration Cellular, Histiocyte                2 (4%)       2 (4%)       3 (6%)                                             
      Thrombosis                                                    1 (2%)                    1 (2%)                                
      Alveolar Epithelium, Hyperplasia                 1 (2%)       2 (4%)       3 (6%)       2 (4%)                                
   Nose                                               (50)         (49)         (49)         (50)                                   
      Foreign Body                                                  1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (49)         (49)         (50)                                   
      Atrophy                                                                                 1 (2%)                                
      Cataract                                                      1 (2%)       2 (4%)                                             
      Inflammation, Chronic                            1 (2%)                    2 (4%)                                             
   Harderian Gland                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)                                                                       
      Hyperplasia, Focal                                            3 (6%)       2 (4%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (49)         (49)         (50)                                   
      Cyst                                             1 (2%)       2 (4%)       1 (2%)       1 (2%)                                
      Hyperplasia, Lymphoid                            8 (16%)     16 (33%)      8 (16%)      4 (8%)                                
      Infarct                                                                    2 (4%)       2 (4%)                                
      Inflammation, Chronic                                                                   1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Metaplasia, Osseous                                           1 (2%)                    2 (4%)                                
      Nephropathy                                     27 (54%)     17 (35%)     21 (43%)     19 (38%)                               
      Papilla, Necrosis                                                                       1 (2%)                                
      Renal Tubule, Accumulation, Hyaline Droplet                   1 (2%)                    1 (2%)                                
      Renal Tubule, Dilatation                                                   1 (2%)                                             
      Renal Tubule, Necrosis                                                     1 (2%)       1 (2%)                                
      Renal Tubule, Pigmentation                                    2 (4%)                                                          
   Urinary Bladder                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia, Lymphoid                           16 (32%)     16 (33%)      6 (12%)     11 (22%)                               
      Inflammation, Chronic                            1 (2%)       1 (2%)                                                          
      Transitional Epithelium, Hyperplasia                          1 (2%)                                                          
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 4            1            5            5                                     
    Natural Death                                      3            3            9            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                43           46           36           40                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (49)         (49)         (47)         (50)                                   
      Edema                                            2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
   Intestine Small, Duodenum                          (49)         (49)         (45)         (50)                                   
      Epithelium, Hyperplasia                                                                 1 (2%)                                
   Intestine Small, Jejunum                           (50)         (49)         (46)         (50)                                   
      Hyperplasia, Lymphoid                                         1 (2%)       1 (2%)                                             
      Infiltration Cellular, Polymorphonuclear                                   1 (2%)                                             
   Intestine Small, Ileum                             (49)         (50)         (45)         (49)                                   
      Hyperplasia, Lymphoid                                         1 (2%)                    1 (2%)                                
      Infiltration Cellular, Polymorphonuclear                                                1 (2%)                                
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)                    1 (2%)                                             
      Basophilic Focus                                 2 (4%)       3 (6%)       1 (2%)       3 (6%)                                
      Clear Cell Focus                                 6 (12%)      9 (18%)      6 (12%)      8 (16%)                               
      Cyst                                                          1 (2%)                                                          
      Eosinophilic Focus                               3 (6%)       3 (6%)       2 (4%)       6 (12%)                               
      Hematopoietic Cell Proliferation                 1 (2%)                    2 (4%)       2 (4%)                                
      Hepatodiaphragmatic Nodule                                                              1 (2%)                                
      Infarct                                          1 (2%)                                                                       
      Infiltration Cellular, Mixed Cell                5 (10%)      7 (14%)      7 (14%)      7 (14%)                               
      Mixed Cell Focus                                 4 (8%)       3 (6%)       4 (8%)       4 (8%)                                
      Necrosis, Diffuse                                                                       1 (2%)                                
      Necrosis, Focal                                  2 (4%)       6 (12%)      2 (4%)       6 (12%)                               
      Tension Lipidosis                                             2 (4%)       1 (2%)                                             
      Hepatocyte, Cytoplasmic Alteration                                        11 (22%)     37 (74%)                               
      Hepatocyte, Karyomegaly                                                   10 (20%)     29 (58%)                               
      Hepatocyte, Vacuolization Cytoplasmic                         1 (2%)                    1 (2%)                                
      Kupffer Cell, Pigmentation                                    1 (2%)       1 (2%)      19 (38%)                               
   Mesentery                                          (6)          (2)          (5)          (2)                                    
      Angiectasis                                                   1 (50%)                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Inflammation, Chronic                                         1 (50%)                                                         
      Fat, Necrosis                                    4 (67%)      1 (50%)      3 (60%)      2 (100%)                              
   Pancreas                                           (50)         (50)         (49)         (50)                                   
      Atrophy                                          1 (2%)                    1 (2%)                                             
      Cyst                                             2 (4%)                    3 (6%)       2 (4%)                                
      Acinus, Cytoplasmic Alteration                                             2 (4%)       1 (2%)                                
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia, Lymphoid                            2 (4%)       2 (4%)                                                          
   Stomach, Forestomach                               (50)         (49)         (50)         (50)                                   
      Diverticulum                                                  2 (4%)                                                          
      Inflammation, Chronic Active                     1 (2%)       1 (2%)                                                          
      Ulcer                                                         1 (2%)                    1 (2%)                                
      Epithelium, Hyperplasia                          2 (4%)       2 (4%)       1 (2%)       1 (2%)                                
   Stomach, Glandular                                 (50)         (49)         (49)         (50)                                   
      Glands, Dysplasia                                1 (2%)                                                                       
   Tooth                                                                                     (1)                                    
      Inflammation, Chronic                                                                   1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   1 (2%)                                 1 (2%)                                
      Perivascular, Inflammation, Chronic              3 (6%)                                                                       
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 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                2 (4%)       6 (12%)      8 (16%)      6 (12%)                               
      Hyperplasia, Focal                               2 (4%)       4 (8%)       3 (6%)       1 (2%)                                
      Hypertrophy, Focal                              13 (26%)     18 (36%)     10 (20%)     10 (20%)                               
      Capsule, Hyperplasia                             1 (2%)       2 (4%)       3 (6%)       2 (4%)                                
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                                                2 (4%)                                             
   Islets, Pancreatic                                 (50)         (50)         (49)         (50)                                   
      Hyperplasia                                                   2 (4%)                    1 (2%)                                
   Parathyroid Gland                                  (49)         (47)         (45)         (48)                                   
      Cyst                                             3 (6%)       1 (2%)       2 (4%)       1 (2%)                                
   Pituitary Gland                                    (49)         (48)         (48)         (50)                                   
      Pars Distalis, Cyst                              2 (4%)       1 (2%)       2 (4%)       2 (4%)                                
      Pars Distalis, Hyperplasia, Focal                             1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Degeneration, Cystic                            10 (20%)      2 (4%)       3 (6%)       4 (8%)                                
      Follicular Cell, Hyperplasia                                  2 (4%)       3 (6%)      33 (66%)                               
      Follicular Cell, Hypertrophy                     1 (2%)                    6 (12%)     25 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Fibrosis                                         1 (2%)                                                                       
      Granuloma Sperm                                                            3 (6%)       6 (12%)                               
      Hyperplasia, Lymphoid                                                      2 (4%)       1 (2%)                                
      Hypospermia                                                                1 (2%)                                             
      Inflammation, Chronic Active                     1 (2%)       3 (6%)       7 (14%)      8 (16%)                               
   Penis                                              (1)                       (1)          (1)                                    
      Angiectasis                                                                1 (100%)     1 (100%)                              
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                            18 (36%)     23 (46%)     16 (32%)     21 (42%)                               
      Inflammation, Chronic                           14 (28%)     10 (20%)     14 (28%)      7 (14%)                               
   Prostate                                           (49)         (50)         (49)         (50)                                   
      Inflammation, Chronic                                                                   2 (4%)                                
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                                                       
   Testes                                             (50)         (50)         (50)         (50)                                   
      Germinal Epithelium, Atrophy                     1 (2%)       4 (8%)       8 (16%)     14 (28%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      4 (8%)      10 (20%)     20 (40%)     42 (84%)                               
   Lymph Node                                         (2)          (3)                       (1)                                    
      Bronchial, Hyperplasia, Lymphoid                              1 (33%)                                                         
   Lymph Node, Mandibular                             (48)         (46)         (45)         (50)                                   
      Atrophy                                          1 (2%)                    2 (4%)       4 (8%)                                
      Ectasia                                                                    1 (2%)                                             
      Hyperplasia, Lymphoid                           10 (21%)     14 (30%)      9 (20%)     13 (26%)                               
      Pigmentation                                     8 (17%)      6 (13%)      9 (20%)      6 (12%)                               
   Lymph Node, Mesenteric                             (47)         (47)         (46)         (48)                                   
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Angiectasis                                                                             1 (2%)                                
      Atrophy                                          1 (2%)       1 (2%)       2 (4%)       2 (4%)                                
      Hemorrhage                                       4 (9%)       2 (4%)       2 (4%)                                             
      Hyperplasia, Lymphoid                            7 (15%)      7 (15%)     15 (33%)     10 (21%)                               
      Necrosis                                         1 (2%)                                 1 (2%)                                
   Spleen                                             (50)         (50)         (49)         (50)                                   
      Angiectasis                                                                             1 (2%)                                
      Atrophy                                                       1 (2%)       4 (8%)       3 (6%)                                
      Hematopoietic Cell Proliferation                10 (20%)     21 (42%)     38 (78%)     45 (90%)                               
      Pigmentation                                     1 (2%)      16 (32%)     33 (67%)     43 (86%)                               
      Lymphoid Follicle, Atrophy                                    4 (8%)      14 (29%)     30 (60%)                               
      Lymphoid Follicle, Hyperplasia                   5 (10%)      2 (4%)       2 (4%)                                             
   Thymus                                             (47)         (46)         (46)         (47)                                   
      Atrophy                                          7 (15%)      5 (11%)      9 (20%)      8 (17%)                               
      Cyst                                             1 (2%)                    1 (2%)       1 (2%)                                
      Hyperplasia, Lymphoid                                         1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                                         1 (2%)                                                          
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 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (1)          (1)                       (2)                                    
      Atrophy                                                                                 1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression                                                   1 (2%)                                                          
   Peripheral Nerve                                   (1)                                    (1)                                    
      Atrophy                                                                                 1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Edema                                            1 (2%)       3 (6%)       1 (2%)       3 (6%)                                
      Hemorrhage                                       4 (8%)       8 (16%)      4 (8%)       2 (4%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         2-METHYLIMIDAZOLE                                     Date: 08/06/04    
Route: DOSED FEED                                                                                                 Time: 09:39:04    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0PPM         625 PPM      1250 PPM     2500 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Hyperplasia, Lymphoid                            1 (2%)       2 (4%)       2 (4%)       4 (8%)                                
      Infiltration Cellular, Histiocyte                4 (8%)       4 (8%)       4 (8%)       2 (4%)                                
      Inflammation, Chronic                                                      1 (2%)       2 (4%)                                
      Metaplasia, Osseous                                                        2 (4%)                                             
      Thrombosis                                       1 (2%)                                 1 (2%)                                
      Alveolar Epithelium, Hyperplasia                 5 (10%)      3 (6%)       1 (2%)       3 (6%)                                
      Alveolar Epithelium, Hyperplasia, Multifocal     1 (2%)                                                                       
   Nose                                               (50)         (50)         (50)         (50)                                   
      Foreign Body                                     1 (2%)       3 (6%)       3 (6%)       2 (4%)                                
      Inflammation, Chronic                            1 (2%)       4 (8%)       3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (50)                                   
      Cataract                                                                   1 (2%)       1 (2%)                                
      Inflammation, Chronic                            1 (2%)       2 (4%)       2 (4%)       2 (4%)                                
      Cornea, Hyperplasia                              1 (2%)                    1 (2%)                                             
   Harderian Gland                                    (50)         (50)         (48)         (50)                                   
      Hyperplasia, Focal                               1 (2%)                    2 (4%)                                             
      Inflammation, Chronic                            3 (6%)       4 (8%)                    2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                            13 (26%)     11 (22%)     12 (24%)     19 (38%)                               
      Hydronephrosis                                   1 (2%)                                                                       
      Hyperplasia, Lymphoid                            1 (2%)       3 (6%)       3 (6%)       3 (6%)                                
      Infarct                                          6 (12%)      6 (12%)      6 (12%)      1 (2%)                                
      Inflammation, Suppurative                                                               1 (2%)                                
      Metaplasia, Osseous                              5 (10%)      3 (6%)       2 (4%)       3 (6%)                                
      Nephropathy                                     34 (68%)     43 (86%)     32 (64%)     31 (62%)                               
      Papilla, Necrosis                                                                       1 (2%)                                
      Renal Tubule, Hyperplasia                        1 (2%)       1 (2%)       2 (4%)       3 (6%)                                
      Renal Tubule, Pigmentation                       1 (2%)                    2 (4%)      45 (90%)                               
   Urethra                                                                                   (1)                                    
      Angiectasis                                                                             1 (100%)                              
      Inflammation, Suppurative                                                               1 (100%)                              
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Transitional Epithelium, Hyperplasia                                                    1 (2%)                                
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                             Page   12                                                              
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
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