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TDMS Study 92013-06 Pathology Tables

NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04
Route: DOSED FEED                                                                                                 Time: 14:34:40

                                                         FINAL #1 MICE




       Facility:  Southern Research Institute

       Chemical CAS #:  822-36-6

       Lock Date:  09/13/02

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All


































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

                                                              Page   1


NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 3            4            3            3                                     
    Natural Death                                      4            6            4            7                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                42           40           41           39                                     
    Natural Death                                      1                         2            1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (49)         (48)         (46)         (46)                                   
      Edema                                            3 (6%)       4 (8%)       2 (4%)       2 (4%)                                
   Intestine Small, Jejunum                           (50)         (48)         (47)         (47)                                   
      Hyperplasia, Lymphoid                            4 (8%)       2 (4%)       2 (4%)                                             
   Intestine Small, Ileum                             (48)         (45)         (48)         (48)                                   
      Hyperplasia, Lymphoid                            1 (2%)                                                                       
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                                                2 (4%)                                             
      Basophilic Focus                                 1 (2%)                    1 (2%)       1 (2%)                                
      Cyst                                             3 (6%)                                 1 (2%)                                
      Eosinophilic Focus                               1 (2%)       2 (4%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                 6 (12%)                   5 (10%)      3 (6%)                                
      Hemorrhage                                                                              1 (2%)                                
      Hyperplasia, Lymphoid                            2 (4%)       3 (6%)       1 (2%)                                             
      Infiltration Cellular, Mixed Cell                1 (2%)       3 (6%)       1 (2%)       1 (2%)                                
      Mixed Cell Focus                                 1 (2%)                    1 (2%)                                             
      Necrosis, Focal                                  4 (8%)       3 (6%)       2 (4%)       6 (12%)                               
      Centrilobular, Necrosis                          1 (2%)                    1 (2%)       1 (2%)                                
      Hepatocyte, Hypertrophy                          1 (2%)                                                                       
      Hepatocyte, Vacuolization Cytoplasmic            1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Kupffer Cell, Pigmentation                       1 (2%)       1 (2%)       2 (4%)                                             
   Mesentery                                          (3)          (7)          (7)          (4)                                    
      Hemorrhage                                                                              1 (25%)                               
      Fat, Necrosis                                    3 (100%)     3 (43%)      3 (43%)      3 (75%)                               
   Pancreas                                           (49)         (48)         (48)         (49)                                   
      Atrophy                                                       1 (2%)                                                          
      Cyst                                             3 (6%)       1 (2%)                                                          
      Hyperplasia, Lymphoid                                         1 (2%)                    1 (2%)                                
      Necrosis                                         1 (2%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Acinus, Cytoplasmic Alteration                   1 (2%)       1 (2%)                                                          
   Salivary Glands                                    (50)         (48)         (50)         (49)                                   
      Atrophy                                                                                 2 (4%)                                
      Hyperplasia, Lymphoid                            3 (6%)       4 (8%)       3 (6%)       3 (6%)                                
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                     2 (4%)                                                                       
      Hyperplasia, Squamous                                                      1 (2%)                                             
      Inflammation, Chronic                                                      1 (2%)       1 (2%)                                
      Ulcer                                            1 (2%)       1 (2%)                                                          
      Epithelium, Hyperplasia                          3 (6%)       5 (10%)      2 (4%)       5 (10%)                               
   Stomach, Glandular                                 (49)         (49)         (50)         (49)                                   
      Erosion                                                                    2 (4%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                            1 (2%)                    1 (2%)                                             
      Mineralization                                                                          4 (8%)                                
      Thrombosis                                                                 1 (2%)                                             
      Myocardium, Necrosis                                          1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                9 (18%)      9 (18%)      9 (18%)      5 (10%)                               
      Hyperplasia, Diffuse                             1 (2%)                                                                       
      Hyperplasia, Focal                                                         1 (2%)       2 (4%)                                
      Capsule, Hyperplasia                                          2 (4%)                                                          
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                                                1 (2%)       2 (4%)                                
   Islets, Pancreatic                                 (49)         (48)         (47)         (49)                                   
      Hyperplasia                                      1 (2%)                                 2 (4%)                                
   Parathyroid Gland                                  (49)         (49)         (48)         (47)                                   
      Cyst                                                          1 (2%)       5 (10%)      2 (4%)                                
   Pituitary Gland                                    (49)         (46)         (49)         (50)                                   
      Pars Distalis, Cyst                              1 (2%)       3 (7%)       4 (8%)                                             
      Pars Distalis, Hyperplasia, Focal                2 (4%)       4 (9%)       1 (2%)                                             
   Thyroid Gland                                      (50)         (49)         (50)         (48)                                   
      Follicle, Cyst                                  20 (40%)     22 (45%)     29 (58%)     30 (63%)                               
      Follicular Cell, Hyperplasia                     1 (2%)                    1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (49)         (50)         (50)                                   
      Inflammation, Chronic                            1 (2%)       3 (6%)       5 (10%)      3 (6%)                                
   Ovary                                              (48)         (49)         (49)         (50)                                   
      Angiectasis                                      9 (19%)      9 (18%)      7 (14%)      6 (12%)                               
      Cyst                                            16 (33%)     20 (41%)     14 (29%)     19 (38%)                               
      Inflammation, Granulomatous                                   1 (2%)                                                          
      Corpus Luteum, Hyperplasia                                                              1 (2%)                                
      Granulosa Cell, Hyperplasia                      1 (2%)       1 (2%)                                                          
      Thecal Cell, Hyperplasia                                                   1 (2%)                                             
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   3 (6%)                    3 (6%)                                
      Hyperplasia, Cystic                             45 (90%)     47 (94%)     46 (92%)     47 (94%)                               
      Inflammation, Chronic                            1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
      Metaplasia, Squamous                             2 (4%)       3 (6%)       1 (2%)       5 (10%)                               
      Thrombosis                                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia                                     13 (26%)     13 (26%)     10 (20%)     17 (34%)                               
      Infiltration Cellular, Mast Cell                              1 (2%)                                                          
   Lymph Node                                         (3)          (9)          (12)         (7)                                    
      Bronchial, Hyperplasia, Lymphoid                                           1 (8%)                                             
      Iliac, Hemorrhage                                             1 (11%)                   1 (14%)                               
      Iliac, Hyperplasia, Lymphoid                                  2 (22%)      1 (8%)       1 (14%)                               
      Iliac, Pigmentation                                                                     1 (14%)                               
      Inguinal, Hyperplasia, Lymphoid                               2 (22%)      1 (8%)                                             
      Mediastinal, Hyperplasia, Lymphoid                            2 (22%)                                                         
      Renal, Hematopoietic Cell Proliferation                                    1 (8%)                                             
      Renal, Hyperplasia, Lymphoid                                               1 (8%)       1 (14%)                               
      Renal, Pigmentation                                                                     1 (14%)                               
   Lymph Node, Mandibular                             (47)         (47)         (48)         (48)                                   
      Hematopoietic Cell Proliferation                 1 (2%)                    2 (4%)                                             
      Hemorrhage                                                                 1 (2%)       3 (6%)                                
      Hyperplasia, Lymphoid                            6 (13%)      8 (17%)      7 (15%)     13 (27%)                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pigmentation                                    12 (26%)     19 (40%)     18 (38%)     19 (40%)                               
   Lymph Node, Mesenteric                             (49)         (47)         (49)         (50)                                   
      Atrophy                                                       2 (4%)                                                          
      Ectasia                                          1 (2%)                    1 (2%)                                             
      Hematopoietic Cell Proliferation                 2 (4%)       1 (2%)       2 (4%)                                             
      Hyperplasia, Lymphoid                            3 (6%)       8 (17%)      9 (18%)     10 (20%)                               
   Spleen                                             (49)         (49)         (49)         (49)                                   
      Hematopoietic Cell Proliferation                15 (31%)     16 (33%)     13 (27%)     11 (22%)                               
      Hyperplasia, Lymphoid                            8 (16%)     11 (22%)      8 (16%)     11 (22%)                               
      Pigmentation                                                  1 (2%)       1 (2%)                                             
      Lymphoid Follicle, Atrophy                       1 (2%)       1 (2%)                    1 (2%)                                
      Lymphoid Follicle, Hyperplasia                  14 (29%)     12 (24%)     12 (24%)     13 (27%)                               
      Red Pulp, Congestion                                                                    1 (2%)                                
   Thymus                                             (49)         (49)         (50)         (48)                                   
      Atrophy                                          3 (6%)       6 (12%)      2 (4%)       5 (10%)                               
      Hyperplasia, Lymphoid                            3 (6%)       1 (2%)       2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (49)         (49)                                   
      Galactocele                                                                             1 (2%)                                
      Hyperplasia                                     16 (32%)     10 (20%)     14 (29%)     24 (49%)                               
   Skin                                               (50)         (50)         (50)         (50)                                   
      Edema                                                                      1 (2%)       1 (2%)                                
      Epidermis, Hyperplasia                                        1 (2%)                                                          
      Subcutaneous Tissue, Inflammation,                                                                                            
        Granulomatous                                  1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Hyperostosis                                    10 (20%)     12 (24%)     10 (20%)      6 (12%)                               
   Skeletal Muscle                                    (1)          (1)          (2)          (2)                                    
      Mineralization                                                                          1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression                                                                             1 (2%)                                
      Hemorrhage                                                    2 (4%)       1 (2%)       2 (4%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
NERVOUS SYSTEM - CONT                                                                                                               
   Peripheral Nerve                                                (2)                       (2)                                    
      Atrophy                                                                                 1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)       2 (4%)       3 (6%)       4 (8%)                                
      Hyperplasia, Lymphoid                            6 (12%)      6 (12%)      8 (16%)      8 (16%)                               
      Infiltration Cellular, Histiocyte                1 (2%)       5 (10%)      1 (2%)       8 (16%)                               
      Metaplasia, Osseous                              1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia                 3 (6%)       2 (4%)       3 (6%)      11 (22%)                               
   Nose                                               (50)         (49)         (50)         (50)                                   
      Inflammation, Chronic                            1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (50)                                   
      Cataract                                                                   2 (4%)       1 (2%)                                
      Inflammation, Chronic                                                      1 (2%)       1 (2%)                                
      Cornea, Hyperplasia                                                        1 (2%)                                             
      Cornea, Mineralization                                                     1 (2%)                                             
      Retina, Degeneration                                                       1 (2%)                                             
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                                   1 (2%)                                                          
      Hyperplasia, Focal                               2 (4%)       3 (6%)       2 (4%)                                             
      Inflammation, Chronic                            1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Cyst                                             1 (2%)       1 (2%)                                                          
      Hydronephrosis                                                1 (2%)                                                          
      Hyperplasia, Lymphoid                            1 (2%)       2 (4%)       6 (12%)      3 (6%)                                
      Metaplasia, Osseous                              1 (2%)       1 (2%)                    1 (2%)                                
      Nephropathy                                     21 (43%)     20 (40%)     17 (34%)     25 (50%)                               
      Renal Tubule, Accumulation, Hyaline Droplet      3 (6%)       2 (4%)       1 (2%)       2 (4%)                                
      Renal Tubule, Hyperplasia                        1 (2%)                                                                       
      Renal Tubule, Necrosis                                        1 (2%)                                                          
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Edema                                                                      1 (2%)       1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Hemorrhage                                                    1 (2%)                                                          
      Hyperplasia, Lymphoid                            1 (2%)       3 (6%)       4 (8%)       3 (6%)                                
      Inflammation, Chronic                            1 (2%)       1 (2%)                                                          
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      4            6            8                                                  
    Moribund Sacrifice                                 1                                      3                                     
  Survivors                                                                                                                         
    Natural Death                                      1                                                                            
    Terminal Sacrifice                                44           44           42           46                                     
  Other                                                                                       1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (49)         (47)         (50)                                   
      Edema                                            3 (6%)       1 (2%)       3 (6%)       4 (8%)                                
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Inflammation                                                               1 (2%)                                             
      Ulcer                                            1 (2%)                    1 (2%)                                             
   Intestine Small, Jejunum                           (48)         (47)         (48)         (50)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Hyperplasia, Lymphoid                            2 (4%)       2 (4%)       3 (6%)       1 (2%)                                
   Intestine Small, Ileum                             (49)         (46)         (48)         (49)                                   
      Hyperplasia, Lymphoid                                         1 (2%)                                                          
   Liver                                              (50)         (50)         (50)         (50)                                   
      Basophilic Focus                                 1 (2%)                    1 (2%)       1 (2%)                                
      Clear Cell Focus                                 3 (6%)       3 (6%)       2 (4%)       3 (6%)                                
      Cyst                                                          1 (2%)                    1 (2%)                                
      Eosinophilic Focus                               5 (10%)      2 (4%)       1 (2%)       1 (2%)                                
      Hyperplasia, Lymphoid                                                                   1 (2%)                                
      Infiltration Cellular, Mixed Cell                                          3 (6%)       1 (2%)                                
      Mixed Cell Focus                                 3 (6%)       7 (14%)      2 (4%)                                             
      Necrosis, Focal                                  2 (4%)       3 (6%)       2 (4%)                                             
      Tension Lipidosis                                1 (2%)                    1 (2%)                                             
      Centrilobular, Necrosis                                                    1 (2%)                                             
      Hepatocyte, Hypertrophy                                       1 (2%)                    1 (2%)                                
      Hepatocyte, Vacuolization Cytoplasmic            4 (8%)       5 (10%)      2 (4%)                                             
   Mesentery                                          (4)          (7)          (2)          (3)                                    
      Hemorrhage                                       1 (25%)                                                                      
      Fat, Necrosis                                    3 (75%)      3 (43%)      2 (100%)     2 (67%)                               
   Pancreas                                           (49)         (49)         (50)         (50)                                   
      Cyst                                                                       1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Acinus, Hyperplasia, Focal                                                              1 (2%)                                
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
      Diverticulum                                                  2 (4%)       1 (2%)       1 (2%)                                
      Erosion                                                                    1 (2%)                                             
      Hyperplasia                                                                             1 (2%)                                
      Inflammation, Chronic                                                      2 (4%)                                             
      Ulcer                                                         1 (2%)       1 (2%)                                             
      Epithelium, Hyperplasia                          3 (6%)       2 (4%)       4 (8%)                                             
   Stomach, Glandular                                 (49)         (50)         (49)         (50)                                   
      Erosion                                          2 (4%)                    1 (2%)       1 (2%)                                
      Glands, Hyperplasia                                                                     1 (2%)                                
   Tooth                                              (4)                                    (3)                                    
      Inflammation, Chronic                            3 (75%)                                2 (67%)                               
      Malformation                                     1 (25%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                            2 (4%)                    2 (4%)       1 (2%)                                
      Mineralization                                                             2 (4%)                                             
      Thrombosis                                                                              1 (2%)                                
      Myocardium, Necrosis                                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                2 (4%)       4 (8%)       6 (12%)      8 (16%)                               
      Hyperplasia, Focal                               3 (6%)       2 (4%)       1 (2%)       1 (2%)                                
      Hypertrophy, Focal                              17 (34%)     11 (22%)     10 (20%)     14 (28%)                               
      Capsule, Hyperplasia                             1 (2%)       1 (2%)       2 (4%)       5 (10%)                               
   Islets, Pancreatic                                 (49)         (49)         (50)         (50)                                   
      Hyperplasia                                      4 (8%)       2 (4%)                    1 (2%)                                
   Parathyroid Gland                                  (47)         (49)         (49)         (49)                                   
      Cyst                                             1 (2%)                    1 (2%)       1 (2%)                                
   Pituitary Gland                                    (49)         (48)         (49)         (50)                                   
      Pars Distalis, Cyst                              1 (2%)       3 (6%)       3 (6%)       2 (4%)                                
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Follicle, Cyst                                  13 (26%)     13 (26%)     13 (26%)     14 (28%)                               
      Follicular Cell, Hyperplasia                                  1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Atypia Cellular                                  1 (2%)       1 (2%)                                                          
      Spermatocele                                     1 (2%)                                 1 (2%)                                
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                            29 (58%)     27 (54%)     31 (62%)     36 (72%)                               
      Inflammation, Chronic                           17 (34%)     19 (38%)     24 (48%)     23 (46%)                               
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Degeneration                                     1 (2%)                                                                       
   Testes                                             (50)         (50)         (50)         (50)                                   
      Germinal Epithelium, Atrophy                                  3 (6%)       1 (2%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia                                     13 (26%)     15 (30%)     14 (28%)     15 (30%)                               
   Lymph Node                                         (2)          (2)          (1)          (2)                                    
      Inguinal, Hyperplasia, Lymphoid                                                         1 (50%)                               
      Inguinal, Pigmentation                           1 (50%)                                                                      
      Pancreatic, Hyperplasia, Lymphoid                                                       1 (50%)                               
   Lymph Node, Mandibular                             (48)         (50)         (48)         (45)                                   
      Hematopoietic Cell Proliferation                              2 (4%)                    1 (2%)                                
      Hyperplasia, Lymphoid                           10 (21%)      8 (16%)      9 (19%)     12 (27%)                               
      Pigmentation                                    10 (21%)      5 (10%)      7 (15%)     12 (27%)                               
   Lymph Node, Mesenteric                             (49)         (48)         (48)         (50)                                   
      Hematopoietic Cell Proliferation                                                        1 (2%)                                
      Hemorrhage                                       4 (8%)       7 (15%)      4 (8%)      14 (28%)                               
      Hyperplasia, Lymphoid                            7 (14%)      4 (8%)       4 (8%)       7 (14%)                               
   Spleen                                             (49)         (49)         (50)         (50)                                   
      Angiectasis                                      1 (2%)       1 (2%)                    1 (2%)                                
      Hematopoietic Cell Proliferation                10 (20%)     14 (29%)      9 (18%)     12 (24%)                               
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)       2 (4%)       2 (4%)                                
      Lymphoid Follicle, Atrophy                                    1 (2%)       1 (2%)       1 (2%)                                
      Lymphoid Follicle, Hyperplasia                  10 (20%)      8 (16%)      2 (4%)       7 (14%)                               
   Thymus                                             (48)         (49)         (45)         (45)                                   
      Atrophy                                          7 (15%)      7 (14%)      5 (11%)      8 (18%)                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (49)                                   
      Cyst Epithelial Inclusion                                                               1 (2%)                                
      Edema                                                         2 (4%)                                                          
      Ulcer                                                                      1 (2%)                                             
      Epidermis, Hyperplasia                           2 (4%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                                        1 (2%)                    1 (2%)                                
   Skeletal Muscle                                    (1)          (2)          (1)          (1)                                    
      Atrophy                                                                                 1 (100%)                              
      Necrosis                                                      1 (50%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)                                                                       
      Inflammation, Chronic                            1 (2%)                                                                       
   Peripheral Nerve                                                                          (2)                                    
      Atrophy                                                                                 1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                                                 1 (2%)       1 (2%)                                
      Hemorrhage                                       3 (6%)       2 (4%)       1 (2%)       5 (10%)                               
      Hyperplasia, Lymphoid                            3 (6%)       2 (4%)       6 (12%)      2 (4%)                                
      Infiltration Cellular, Histiocyte                5 (10%)      6 (12%)      5 (10%)     11 (22%)                               
      Metaplasia, Osseous                                                        1 (2%)                                             
      Thrombosis                                       1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia                 7 (14%)      3 (6%)       1 (2%)       9 (18%)                               
      Bronchiole, Epithelium, Hyperplasia                                        1 (2%)       1 (2%)                                
   Nose                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                            1 (2%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                                                                                                    
                                                                                                                                    
                                                             Page   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03  
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04    
Route: DOSED FEED                                                                                                 Time: 14:34:40    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (50)                                   
      Cataract                                         1 (2%)                                 2 (4%)                                
      Inflammation, Chronic                            1 (2%)                                 1 (2%)                                
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia, Focal                               1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                            13 (26%)     12 (24%)     12 (24%)      7 (14%)                               
      Hydronephrosis                                                             1 (2%)       1 (2%)                                
      Hyperplasia, Lymphoid                            2 (4%)       2 (4%)                    2 (4%)                                
      Inflammation, Chronic Active                                  1 (2%)                                                          
      Metaplasia, Osseous                              2 (4%)       3 (6%)                    2 (4%)                                
      Mineralization                                                             2 (4%)                                             
      Nephropathy                                     34 (68%)     40 (80%)     38 (76%)     35 (70%)                               
      Renal Tubule, Necrosis                                                     1 (2%)                                             
   Urinary Bladder                                    (50)         (49)         (49)         (50)                                   
      Edema                                            1 (2%)       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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