Share This:
https://ntp.niehs.nih.gov/go/10191

TDMS Study 92012-05 Pathology Tables

NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10

                                                      FINAL#1; REVISION#1




       Facility:  Southern Research Institute

       Chemical CAS #:  693-98-1

       Lock Date:  10/16/01

       Cage Range:  All

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

       Removal Date Range:     All

       Treatment Groups:       Include All
































a  Number of animals examined microscopically at site and number of animals with lesion
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)

                                                              Page   1


NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Natural Death                                      4            3           10            1                                     
    Moribund Sacrifice                                 6            8           12            7                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                40           39           28           41                                     
    Natural Death                                                                             1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (48)         (47)         (44)         (50)                                   
      Edema                                                                                   1 [3.0]                               
   Intestine Small, Jejunum                           (47)         (46)         (44)         (49)                                   
      Necrosis, Focal                                                                         1 [3.0]                               
   Liver                                              (50)         (49)         (50)         (50)                                   
      Angiectasis, Focal                               2 [2.0]      1 [2.0]      2 [3.5]                                            
      Basophilic Focus                                42           44           43           39                                     
      Cholangiofibrosis                                                                       1 [2.0]                               
      Congestion                                                                 2 [2.5]      1 [4.0]                               
      Congestion, Focal                                                          1 [2.0]                                            
      Degeneration, Cystic, Focal                                   1 [2.0]                   2 [2.0]                               
      Eosinophilic Focus                                                         1                                                  
      Fatty Change                                                  2 [3.0]      1 [2.0]                                            
      Hemorrhage                                       2 [2.0]                                2 [2.0]                               
      Hepatodiaphragmatic Nodule                       6           11           14           13                                     
      Hyperplasia, Focal, Lymphoid                                               1 [3.0]      1 [2.0]                               
      Infarct                                                                                 2                                     
      Infiltration Cellular, Mixed Cell               42 [1.7]     44 [2.0]     34 [1.9]     38 [1.9]                               
      Inflammation, Granulomatous                     18 [1.6]     23 [2.0]     22 [1.5]     42 [2.1]                               
      Mixed Cell Focus                                15           14           11           26                                     
      Necrosis, Focal                                               1 [2.0]                   1 [2.0]                               
      Bile Duct, Cholangiofibrosis, Focal                                        1 [2.0]                                            
      Bile Duct, Cyst                                  2                                                                            
      Bile Duct, Cyst, Multiple                                                  1            1                                     
      Bile Duct, Hyperplasia                          20 [1.3]     29 [1.4]     20 [1.5]     40 [1.9]                               
      Hepatocyte, Necrosis, Focal                                                1 [2.0]      2 [2.0]                               
      Hepatocyte, Vacuolization Cytoplasmic, Focal     9 [1.4]     10 [1.4]     11 [1.2]      9 [1.8]                               
      Hepatocyte, Periportal, Vacuolization                                                                                         
        Cytoplasmic                                                              1 [2.0]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatocyte, Centrilobular, Necrosis                                        1 [3.0]      1 [3.0]                               
      Hepatocyte, Centrilobular, Vacuolization                                                                                      
        Cytoplasmic                                    1 [4.0]                   4 [3.0]      1 [2.0]                               
   Mesentery                                          (8)          (10)         (12)         (9)                                    
      Fibrosis                                                      1 [1.0]                                                         
      Hemorrhage, Focal                                                                       1 [2.0]                               
      Infiltration Cellular, Mixed Cell                                          1 [2.0]                                            
      Inflammation, Chronic                                         1 [2.0]                                                         
      Artery, Inflammation, Chronic, Focal                                                    1 [3.0]                               
      Fat, Necrosis                                                 1 [2.0]      2 [2.5]                                            
      Fat, Necrosis, Focal                             5 [2.0]      7 [2.7]      6 [2.8]      3 [2.0]                               
   Pancreas                                           (50)         (49)         (49)         (50)                                   
      Infiltration Cellular, Diffuse, Mixed Cell                    1 [2.0]                                                         
      Acinus, Atrophy, Diffuse                         1 [3.0]      1 [4.0]                   1 [2.0]                               
      Acinus, Atrophy, Focal                          13 [1.6]     14 [1.2]     13 [1.7]     11 [1.9]                               
      Duct, Cyst, Focal                                1 [2.0]                                1 [2.0]                               
      Duct, Cyst, Focal, Multiple                      9 [1.8]     12 [1.9]      4 [2.0]      5 [1.8]                               
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
      Duct, Mineralization, Focal                                                             2 [2.5]                               
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                     1 [2.0]      1 [2.0]                   2 [1.5]                               
      Edema                                                                                   1 [3.0]                               
      Erosion                                                                    1 [2.0]                                            
      Inflammation, Chronic                                         1 [3.0]      1 [3.0]                                            
      Inflammation, Focal                                                        1 [2.0]                                            
      Ulcer                                                         2 [2.5]      1 [2.0]      1 [2.0]                               
      Epithelium, Hyperplasia                          3 [1.3]      1 [2.0]      4 [2.5]      1 [2.0]                               
   Stomach, Glandular                                 (49)         (49)         (48)         (50)                                   
      Erosion                                                       1 [2.0]      1 [2.0]                                            
      Inflammation, Chronic                                                      1 [2.0]                                            
      Necrosis, Focal                                                            1 [2.0]                                            
      Ulcer                                            1 [2.0]                                                                      
      Epithelium, Hyperplasia, Focal                   1 [2.0]                                                                      
      Glands, Degeneration, Cystic, Focal                                        1 [1.0]                                            
      Glands, Ectasia, Focal                           1 [2.0]                                                                      
      Glands, Hyperplasia, Focal                                                              2 [2.0]                               
   Tongue                                             (3)                       (1)                                                 
      Epithelium, Hyperplasia, Focal                   1 [1.0]                                                                      
   Tooth                                              (1)                                                                           
      Peridontal Tissue, Inflammation, Chronic         1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                   5 [1.4]      8 [1.9]      7 [1.6]      6 [1.7]                               
      Infiltration Cellular, Mixed Cell                             4 [1.5]      3 [2.0]      2 [1.5]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                2 [1.0]      2 [1.0]      5 [1.2]      5 [1.0]                               
      Angiectasis                                      1 [2.0]      1 [3.0]      1 [2.0]      2 [2.0]                               
      Cytoplasmic Alteration, Focal                    3 [1.7]                   1 [1.0]      5 [1.4]                               
      Hematopoietic Cell Proliferation                              1 [2.0]                                                         
      Hemorrhage                                                    1 [2.0]                                                         
      Hemorrhage, Focal                                             1 [2.0]                                                         
      Vacuolization Cytoplasmic, Focal                 8 [1.8]      3 [2.0]      7 [1.9]     12 [1.6]                               
   Adrenal Medulla                                    (49)         (49)         (50)         (50)                                   
      Hyperplasia, Focal                               1 [2.0]      1 [2.0]      1 [1.0]      2 [1.0]                               
   Pituitary Gland                                    (50)         (48)         (50)         (50)                                   
      Angiectasis                                      5 [2.8]      9 [2.6]      7 [2.7]      2 [3.0]                               
      Cyst                                                          1 [3.0]                                                         
      Hemorrhage                                                    1 [3.0]                                                         
      Metaplasia, Focal, Lipocyte                                                1 [2.0]                                            
      Pars Distalis, Angiectasis                                                              1 [2.0]                               
      Pars Distalis, Cyst                              1 [3.0]      3 [2.3]      2 [2.0]      1 [2.0]                               
      Pars Distalis, Cyst, Multiple                                 2 [2.5]                                                         
      Pars Distalis, Cytoplasmic Alteration, Focal     4 [1.5]      4 [1.5]      1 [2.0]      3 [1.7]                               
      Pars Distalis, Degeneration, Cystic              1 [2.0]                                                                      
      Pars Distalis, Degeneration, Cystic, Focal       9 [2.2]     14 [2.1]      8 [2.4]      5 [2.2]                               
      Pars Distalis, Hemorrhage, Focal                 1 [1.0]      3 [2.7]      4 [3.0]      6 [2.7]                               
      Pars Distalis, Hyperplasia, Focal                1 [2.0]      1 [2.0]      1 [3.0]      1 [2.0]                               
      Pars Distalis, Pigmentation, Focal                                         1 [2.0]                                            
      Pars Intermedia, Cyst                                                      1 [2.0]      3 [2.0]                               
      Pars Intermedia, Degeneration, Cystic, Focal                                            1 [2.0]                               
      Pars Intermedia, Hemorrhage                                                             1 [2.0]                               
      Pars Intermedia, Pars Nervosa, Atypia                                                                                         
        Cellular, Focal                                             1 [2.0]                                                         
      Rathke's Cleft, Cyst                             1 [3.0]                   1 [2.0]                                            
      Rathke's Cleft, Hemorrhage                                                              2 [3.0]                               
   Thyroid Gland                                      (49)         (48)         (42)         (48)                                   
      Vacuolization Cytoplasmic, Focal                              1 [1.0]                                                         
      C-Cell, Hyperplasia                             48 [2.2]     46 [2.2]     40 [2.0]     25 [1.7]                               
      Follicle, Cyst                                                2            1                                                  
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Follicle, Mineralization, Focal                 42 [1.0]     47 [1.7]     41 [2.4]     48 [2.7]                               
      Follicular Cell, Hyperplasia                                 41 [1.5]     34 [1.7]     46 [2.2]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (3)                       (4)          (2)                                    
      Mediastinum, Infiltration Cellular, Mixed                                                                                     
        Cell                                                                     1 [3.0]                                            
      Pelvic, Hemorrhage, Focal                                                               1 [3.0]                               
      Thoracic, Infiltration Cellular, Focal,                                                                                       
        Mixed Cell                                                               1 [3.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (49)         (50)         (50)                                   
      Degeneration, Cystic                             6 [2.5]      4 [3.0]      1 [2.0]      1 [3.0]                               
      Fibrosis, Focal                                               1 [2.0]                                                         
      Hyperplasia, Cystic                              1 [2.0]      4 [2.8]      3 [3.0]      1 [3.0]                               
      Inflammation, Chronic                            2 [3.0]      5 [2.2]      4 [2.3]                                            
   Ovary                                              (50)         (49)         (50)         (50)                                   
      Angiectasis                                      1 [2.0]      1 [2.0]                                                         
      Atrophy                                                       1 [3.0]                                                         
      Congestion                                                                 1 [3.0]                                            
      Cyst                                             5 [2.0]      5 [2.8]      1 [2.0]                                            
      Bilateral, Cyst, Multiple                                                  1 [4.0]                                            
      Periovarian Tissue, Cyst                         4 [3.3]      5 [3.2]      4 [3.0]      6 [3.0]                               
      Periovarian Tissue, Cyst, Multiple               1 [2.0]                                                                      
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             3 [2.7]                   1 [2.0]      1 [2.0]                               
      Hemorrhage                                                                 2 [2.0]                                            
      Inflammation, Chronic                                                      1 [3.0]                                            
      Cervix, Hyperplasia                                                        1 [3.0]                                            
      Endometrium, Hyperplasia, Cystic                10 [1.7]     14 [1.8]     15 [1.6]     15 [1.6]                               
   Vagina                                             (2)                       (2)                                                 
      Inflammation, Chronic                                                      1 [2.0]                                            
      Epithelium, Cyst                                 1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Atrophy                                          1 [3.0]                                                                      
      Fibrosis                                                                                1 [3.0]                               
      Hyperplasia, Focal, Histiocytic                               1 [2.0]                   4 [2.3]                               
      Myelofibrosis                                                                           1 [3.0]                               
      Necrosis                                                                                1 [2.0]                               
      Myeloid Cell, Hyperplasia                        2 [3.0]      3 [2.7]      5 [2.6]      2 [3.0]                               
      Myeloid Cell, Erythroid Cell, Hyperplasia                     2 [2.5]      1 [3.0]                                            
   Lymph Node                                         (32)         (31)         (34)         (41)                                   
      Deep Cervical, Hemorrhage                                                               2 [3.0]                               
      Mediastinal, Angiectasis                         1 [3.0]                                                                      
      Mediastinal, Congestion                                                    1 [3.0]                                            
      Mediastinal, Ectasia                             5 [2.8]      3 [2.7]      2 [3.0]      7 [2.9]                               
      Mediastinal, Hemorrhage                          2 [2.0]      3 [3.0]      9 [2.8]      8 [2.9]                               
      Mediastinal, Hyperplasia                                      1 [3.0]      2 [3.0]                                            
      Mediastinal, Hyperplasia, Histiocytic            8 [2.9]      8 [2.9]      5 [3.0]     12 [3.0]                               
      Mediastinal, Hyperplasia, Lymphoid                            1 [3.0]      1 [3.0]      1 [3.0]                               
      Mediastinal, Pigmentation                        1 [2.0]                   2 [3.0]                                            
      Pancreatic, Atrophy                                           1 [3.0]                                                         
      Pancreatic, Ectasia                              2 [2.0]      2 [3.0]                  11 [2.7]                               
      Pancreatic, Hemorrhage                           5 [2.6]      3 [3.0]      2 [2.5]      9 [3.0]                               
      Pancreatic, Hyperplasia, Histiocytic            16 [2.8]     24 [2.8]     17 [3.0]     18 [3.1]                               
      Pancreatic, Hyperplasia, Plasma Cell             1 [3.0]                                                                      
      Pancreatic, Infiltration Cellular, Mixed Cell                                           1 [3.0]                               
      Pancreatic, Pigmentation                         4 [2.8]      2 [2.5]                   1 [3.0]                               
   Lymph Node, Mandibular                             (5)          (4)          (5)          (1)                                    
      Ectasia                                          1 [3.0]                                                                      
   Lymph Node, Mesenteric                             (49)         (49)         (49)         (50)                                   
      Angiectasis                                                                1 [3.0]                                            
      Ectasia                                          1 [3.0]                                5 [3.0]                               
      Hemorrhage                                       1 [2.0]                   2 [3.0]      2 [3.0]                               
      Hyperplasia, Histiocytic                         2 [3.0]      1 [3.0]      2 [3.0]      2 [3.0]                               
      Hyperplasia, Lymphoid                                         1 [3.0]                                                         
      Pigmentation                                     2 [2.5]                                                                      
   Spleen                                             (50)         (49)         (48)         (50)                                   
      Accessory Spleen                                              1 [1.0]      1 [2.0]                                            
      Angiectasis, Focal                                            1 [2.0]                                                         
      Congestion                                                    1 [3.0]                                                         
      Fibrosis, Focal                                               1 [2.0]      1 [2.0]                                            
      Hematopoietic Cell Proliferation                 6 [2.2]      8 [2.4]      5 [2.6]      4 [2.0]                               
      Hemorrhage                                                                 1 [2.0]                                            
      Infarct                                                                                 1 [3.0]                               
      Inflammation, Granulomatous                      3 [3.3]      2 [3.0]      4 [2.5]     27 [3.3]                               
      Pigmentation                                                  1 [3.0]                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pigmentation, Focal                              1 [2.0]      1 [3.0]      1 [3.0]                                            
   Thymus                                             (48)         (45)         (49)         (49)                                   
      Angiectasis                                                                2 [3.0]                                            
      Hyperplasia, Lymphoid                            1 [3.0]      1 [3.0]                   2 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Dilatation                                      33 [2.4]     35 [2.5]     22 [2.6]     19 [2.3]                               
      Ectasia                                          2 [3.5]      3 [2.3]      7 [2.3]                                            
      Fibrosis                                                      1 [3.0]                                                         
      Hyperplasia                                      3 [2.3]      5 [2.6]      4 [2.0]      3 [2.0]                               
      Hyperplasia, Cystic                              1 [3.0]                   2 [2.5]                                            
      Inflammation, Focal                                           1 [3.0]                                                         
   Skin                                               (50)         (50)         (50)         (50)                                   
      Necrosis, Focal                                                                         4 [3.3]                               
      Ulcer                                                                      1 [3.0]      1 [4.0]                               
      Subcutaneous Tissue, Angiectasis, Focal                                                 1 [2.0]                               
      Subcutaneous Tissue, Hemorrhage, Focal                                                  1 [3.0]                               
      Subcutaneous Tissue, Inflammation, Focal,                                                                                     
         Suppurative                                                                          1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (50)         (50)                                   
      Compression, Focal                              10 [2.9]      8 [3.0]     12 [2.9]      4 [3.0]                               
      Hemorrhage, Focal                                2 [2.5]      1 [2.0]      2 [3.0]                                            
      Necrosis, Focal                                                            2 [3.0]                                            
      Pigmentation, Focal                                                        1 [2.0]                                            
      Cerebellum, Developmental Malformation                                     1 [3.0]                                            
   Spinal Cord                                        (3)          (1)          (4)                                                 
      Hemorrhage, Focal                                1 [2.0]                                                                      
      Necrosis, Focal                                  1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (49)         (50)         (50)                                   
      Congestion                                       2 [1.5]      4 [2.3]      2 [2.0]      2 [1.5]                               
      Emphysema                                                                  1 [3.0]                                            
      Hemorrhage                                       1 [1.0]                                                                      
      Hemorrhage, Focal                                1 [2.0]                                2 [2.5]                               
      Hyperplasia, Focal, Histiocytic                                            1 [1.0]      1 [3.0]                               
      Hyperplasia, Histiocytic                         6 [1.3]      6 [1.2]      7 [1.0]      1 [2.0]                               
      Infiltration Cellular, Focal, Mixed Cell                                                1 [2.0]                               
      Infiltration Cellular, Mixed Cell                             3 [2.0]      1 [3.0]      6 [2.0]                               
      Inflammation, Chronic, Focal                     1 [1.0]      2 [1.0]      1 [2.0]                                            
      Inflammation, Focal, Granulomatous               1 [1.0]                                1 [1.0]                               
      Pigmentation, Focal                              1 [2.0]                                                                      
      Alveolar Epithelium, Hyperplasia, Focal          7 [1.6]      5 [1.8]      3 [1.7]      3 [2.0]                               
      Alveolus, Inflammation, Focal, Granulomatous                                            1 [2.0]                               
      Interstitium, Edema                                                        1 [3.0]                                            
   Nose                                               (50)         (49)         (50)         (50)                                   
      Foreign Body                                                  1 [2.0]                   1 [3.0]                               
      Inflammation, Suppurative                        1 [2.0]      1 [2.0]                   2 [2.5]                               
      Nasolacrimal Duct, Inflammation                  4 [2.8]      2 [2.0]      4 [2.3]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (49)         (49)         (50)                                   
      Atrophy                                          1 [3.0]      1 [3.0]      1 [3.0]                                            
      Cataract                                         1 [3.0]      2 [3.0]      2 [1.5]      1 [3.0]                               
      Iris, Synechia                                                             1 [3.0]                                            
      Retina, Degeneration                                          2 [3.0]      1 [3.0]      1 [3.0]                               
   Harderian Gland                                    (50)         (49)         (50)         (50)                                   
      Hyperplasia, Cystic, Focal                       1 [2.0]                                                                      
      Hyperplasia, Focal                               2 [1.0]                   1 [2.0]      1 [1.0]                               
      Hyperplasia, Focal, Histiocytic                  1 [2.0]      2 [1.5]      1 [2.0]      4 [1.5]                               
      Inflammation, Chronic, Focal                                               3 [1.3]      1 [3.0]                               
      Inflammation, Focal, Granulomatous                                         1 [1.0]                                            
      Epithelium, Hyperplasia, Focal                                2 [1.5]      2 [2.0]      1 [1.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (48)         (47)         (50)                                   
      Atrophy, Focal                                                2 [2.0]      1 [2.0]                                            
      Congestion                                                                 2 [3.0]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0PPM         1000 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Cyst                                                                                    1 [2.0]                               
      Infarct                                                                    1 [2.0]                                            
      Nephropathy                                     38 [1.0]     40 [1.0]     38 [1.1]     40 [1.1]                               
      Glomerulus, Amyloid Deposition, Diffuse                                                 1 [3.0]                               
      Pelvis, Inflammation                                                       1 [2.0]                                            
      Renal Tubule, Accumulation, Hyaline Droplet     11 [2.2]      7 [2.0]      3 [2.3]      4 [2.5]                               
      Renal Tubule, Pigmentation                       8 [1.6]      4 [1.5]      5 [2.2]                                            
   Urethra                                                                                   (2)                                    
      Transitional Epithelium, Hyperplasia, Diffuse                                           1 [2.0]                               
   Urinary Bladder                                    (50)         (49)         (49)         (50)                                   
      Transitional Epithelium, Hyperplasia                                                    2 [3.0]                               
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                13            6            7           13                                     
    Natural Death                                      2            4            7            2                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                34           39           35           35                                     
    Moribund Sacrifice                                 1                                                                            
    Natural Death                                                   1            1                                                  
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Rectum                            (49)         (48)         (48)         (50)                                   
      Angiectasis, Focal                                                         1 [2.0]                                            
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis, Focal                                                         1 [3.0]                                            
      Basophilic Focus                                23           23            8            2                                     
      Cholangiofibrosis                                1 [4.0]                                1 [2.0]                               
      Congestion                                                                 2 [3.0]      1 [3.0]                               
      Degeneration, Cystic, Focal                      4 [1.8]      3 [1.3]      2 [2.0]      7 [1.7]                               
      Eosinophilic Focus                               3                         6            1                                     
      Fibrosis, Focal                                                            1 [3.0]                                            
      Hematopoietic Cell Proliferation                                                        2 [1.0]                               
      Hepatodiaphragmatic Nodule                       6            5            4            9                                     
      Hyperplasia, Focal, Lymphoid                     1 [2.0]                   2 [2.0]      1 [3.0]                               
      Infiltration Cellular, Mixed Cell               25 [2.0]     30 [1.9]     27 [1.9]     36 [1.9]                               
      Inflammation, Granulomatous                     12 [1.3]     11 [1.2]      4 [1.8]     11 [1.4]                               
      Mixed Cell Focus                                14           16           23           26                                     
      Necrosis, Focal                                  2 [2.5]                   2 [2.5]      1 [2.0]                               
      Pigmentation, Focal                                                        2 [2.5]                                            
      Bile Duct, Cyst                                                                         1                                     
      Bile Duct, Hyperplasia                          49 [2.7]     49 [2.6]     47 [2.7]     49 [2.8]                               
      Centrilobular, Congestion                                                  1 [3.0]                                            
      Hepatocyte, Necrosis, Focal                      1 [4.0]      1 [1.0]      3 [2.0]      2 [1.5]                               
      Hepatocyte, Vacuolization Cytoplasmic,                                                                                        
        Diffuse                                                     1 [2.0]                   1 [2.0]                               
      Hepatocyte, Vacuolization Cytoplasmic, Focal    23 [1.8]     30 [1.8]     26 [1.7]     23 [1.6]                               
      Hepatocyte, Centrilobular, Necrosis                           2 [2.5]      2 [2.5]                                            
      Hepatocyte, Centrilobular, Vacuolization                                                                                      
        Cytoplasmic                                    5 [2.8]      4 [2.8]                   3 [2.3]                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatocyte, Midzonal, Vacuolization                                                                                           
        Cytoplasmic                                    1 [2.0]      1 [2.0]      2 [2.5]                                            
      Oval Cell, Hyperplasia                                                                  1 [2.0]                               
      Serosa, Fibrosis, Focal                                       2 [2.5]                                                         
   Mesentery                                          (26)         (46)         (35)         (20)                                   
      Fibrosis, Focal                                                                         1 [3.0]                               
      Hemorrhage                                                                              2 [3.5]                               
      Necrosis, Focal                                                                         1 [3.0]                               
      Artery, Inflammation, Chronic                                                           1 [3.0]                               
      Fat, Necrosis                                    1 [2.0]      1 [3.0]      2 [2.5]                                            
      Fat, Necrosis, Focal                             8 [2.9]     10 [2.7]     16 [2.8]     10 [2.7]                               
   Pancreas                                           (49)         (49)         (50)         (50)                                   
      Atrophy, Diffuse                                                           1 [3.0]                                            
      Atrophy, Focal                                                             1 [2.0]      1 [2.0]                               
      Fibrosis, Focal                                                                         1 [3.0]                               
      Acinus, Atrophy, Diffuse                                      1 [4.0]                   1 [3.0]                               
      Acinus, Atrophy, Focal                          22 [1.9]     27 [1.9]     20 [2.0]     36 [2.0]                               
      Acinus, Hyperplasia, Focal                                                 1 [3.0]                                            
      Duct, Cyst                                       1 [1.0]                                                                      
      Duct, Cyst, Focal                                             1 [4.0]                                                         
      Duct, Cyst, Focal, Multiple                      6 [2.7]      2 [2.0]      5 [2.0]     12 [1.9]                               
      Duct, Hyperplasia, Cystic                                     1 [2.0]      1 [2.0]                                            
      Duct, Hyperplasia, Cystic, Focal                              2 [2.0]      3 [2.0]                                            
      Duct, Hyperplasia, Focal                                      1 [2.0]                                                         
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy, Focal                                                                          1 [1.0]                               
      Inflammation, Chronic                                                                   1 [2.0]                               
   Stomach, Forestomach                               (50)         (50)         (50)         (49)                                   
      Diverticulum                                     1 [1.0]      1 [1.0]      2 [1.5]      1 [2.0]                               
      Edema                                            1 [3.0]                                                                      
      Erosion                                                       1 [2.0]                   1 [1.0]                               
      Inflammation, Focal                              1 [2.0]                                1 [2.0]                               
      Ulcer                                            2 [1.5]      1 [2.0]      1 [2.0]      4 [2.0]                               
      Epithelium, Hyperplasia                          2 [2.0]      3 [2.7]                   6 [2.0]                               
      Epithelium, Hyperplasia, Focal                                                          1 [2.0]                               
      Serosa, Foreign Body                                                                    1 [1.0]                               
      Serosa, Inflammation, Chronic, Focal                                                    1 [2.0]                               
   Stomach, Glandular                                 (50)         (50)         (50)         (49)                                   
      Erosion                                          4 [1.8]      1 [1.0]      1 [2.0]                                            
      Erosion, Focal                                   1 [2.0]                   1 [3.0]                                            
      Inflammation, Focal                              1 [2.0]                                                                      
      Ulcer                                            2 [1.0]                                                                      
      Epithelium, Necrosis, Focal                                                             1 [1.0]                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Glands, Hyperplasia, Cystic, Focal                            1 [2.0]                                                         
      Glands, Hyperplasia, Focal                       1 [1.0]                                                                      
   Tongue                                             (1)          (2)                       (1)                                    
      Epithelium, Hyperplasia, Focal                                                          1 [2.0]                               
   Tooth                                              (1)          (1)          (1)          (2)                                    
      Malformation                                                  1 [2.0]                                                         
      Peridontal Tissue, Inflammation                  1 [3.0]                                                                      
      Peridontal Tissue, Inflammation, Chronic                                                1 [2.0]                               
      Peridontal Tissue, Inflammation, Focal,                                                                                       
        Suppurative                                                              1 [3.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   3 [1.7]      5 [1.6]     10 [2.0]      5 [2.0]                               
      Cardiomyopathy, Focal                                                      2 [2.0]      1 [2.0]                               
      Congestion                                                                 1 [3.0]                                            
      Fibrosis                                                                                1 [2.0]                               
      Infiltration Cellular, Mixed Cell                             1 [2.0]                                                         
      Thrombosis                                       1 [3.0]      1 [3.0]                                                         
      Endocardium, Myocardium, Fibrosis, Focal         1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                1 [2.0]      4 [1.3]      9 [1.1]      5 [1.6]                               
      Cytoplasmic Alteration, Focal                    2 [2.0]      1 [1.0]      1 [1.0]      3 [1.3]                               
      Degeneration, Cystic, Focal                                                1 [2.0]                                            
      Hemorrhage                                       2 [1.5]                                                                      
      Vacuolization Cytoplasmic, Focal                 6 [1.5]      9 [1.4]     10 [1.3]     10 [1.4]                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   1 [2.0]                                                         
      Hyperplasia                                      1 [2.0]      1 [1.0]                   1 [2.0]                               
      Hyperplasia, Focal                               7 [1.3]      5 [2.2]      3 [1.3]      7 [1.4]                               
      Infiltration Cellular, Lymphoid                               1 [2.0]                                                         
      Vacuolization Cytoplasmic, Focal                              1 [2.0]                                                         
   Islets, Pancreatic                                 (50)         (49)         (50)         (50)                                   
      Atrophy                                                       1 [3.0]                                                         
      Hyperplasia, Focal                                            2 [2.0]      1 [3.0]      1 [2.0]                               
   Parathyroid Gland                                  (47)         (49)         (48)         (49)                                   
      Cyst                                                          1 [3.0]                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   12                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hyperplasia                                                                             1 [3.0]                               
      Hyperplasia, Focal                               1 [2.0]                   1 [3.0]                                            
      Bilateral, Hyperplasia, Focal                    1 [2.0]                                                                      
   Pituitary Gland                                    (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 [1.5]                   3 [2.7]                                            
      Pars Distalis, Angiectasis                       3 [2.3]      2 [2.5]      2 [2.0]      1 [2.0]                               
      Pars Distalis, Cyst                              1 [2.0]      4 [1.3]      2 [2.5]      3 [2.0]                               
      Pars Distalis, Cytoplasmic Alteration, Focal     1 [1.0]      4 [1.8]      2 [1.5]      5 [1.0]                               
      Pars Distalis, Degeneration, Cystic, Focal       1 [2.0]      1 [2.0]      1 [2.0]      1 [1.0]                               
      Pars Distalis, Hyperplasia, Focal                2 [1.5]      1 [2.0]                   2 [1.5]                               
      Pars Distalis, Inflammation, Chronic, Focal,                                                                                  
         Granulomatous                                                           1 [2.0]                                            
      Pars Distalis, Pars Intermedia, Angiectasis                   1 [3.0]                                                         
      Pars Intermedia, Cyst                                         2 [1.5]                   1 [2.0]                               
      Pars Intermedia, Hemorrhage                                                1 [2.0]                                            
      Pars Intermedia, Hyperplasia, Focal                           1 [1.0]                                                         
      Pars Nervosa, Infiltration Cellular, Focal,                                                                                   
         Mixed Cell                                                              1 [2.0]                                            
   Thyroid Gland                                      (48)         (46)         (43)         (50)                                   
      Cyst                                                          1                                                               
      C-Cell, Hyperplasia                             41 [1.7]     43 [1.7]     38 [1.5]     34 [1.7]                               
      Follicle, Cyst                                   1                                      1                                     
      Follicle, Mineralization, Focal                 48 [1.0]     45 [1.0]     43 [1.9]     49 [2.7]                               
      Follicular Cell, Atrophy, Focal                  1 [1.0]                                                                      
      Follicular Cell, Hyperplasia                                 17 [1.1]     37 [1.1]     43 [1.8]                               
      Follicular Cell, Hyperplasia, Cystic, Focal      1 [2.0]                                1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (7)          (2)          (6)          (4)                                    
      Mediastinum, Hemorrhage                                                                 1 [3.0]                               
      Thoracic, Hemorrhage                                                                    1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Atrophy                                                       1 [3.0]                   1 [2.0]                               
      Granuloma Sperm                                               1 [2.0]      1 [4.0]      1 [2.0]                               
      Inflammation, Chronic                                         1 [3.0]      1 [2.0]                                            
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                             1 [3.0]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   13                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Degeneration, Cystic                                                                    2 [2.5]                               
      Hyperplasia                                                                1 [2.0]                                            
      Hyperplasia, Cystic                              2 [3.0]                   2 [3.0]      1 [4.0]                               
      Hyperplasia, Focal                               1 [2.0]                                                                      
      Inflammation, Chronic                            4 [2.0]     10 [1.6]     10 [1.7]     11 [2.0]                               
      Inflammation, Chronic, Focal                                  1 [1.0]                                                         
      Inflammation, Suppurative                                     1 [3.0]      1 [3.0]      2 [3.5]                               
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 [3.0]                                                                      
      Hyperplasia, Focal                                            1 [1.0]                                                         
      Inflammation, Chronic                           15 [1.8]     10 [1.9]     17 [1.6]     19 [1.5]                               
      Epithelium, Degeneration, Focal, Mucoid          1 [2.0]                                                                      
      Epithelium, Hyperplasia, Focal                   4 [1.3]      2 [1.5]                   5 [1.2]                               
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          5 [3.2]      4 [3.8]     13 [3.1]     13 [3.2]                               
      Mineralization, Focal                            1 [1.0]                                                                      
      Bilateral, Atrophy                               2 [3.5]      3 [3.3]      2 [3.0]                                            
      Bilateral, Interstitial Cell, Hyperplasia,                                                                                    
         Focal                                                                                2 [1.5]                               
      Germinal Epithelium, Atrophy                     2 [2.5]      3 [3.3]      1 [3.0]      1 [3.0]                               
      Interstitial Cell, Hyperplasia                                2 [1.5]      1 [1.0]      1 [2.0]                               
      Interstitial Cell, Hyperplasia, Focal            1 [1.0]      4 [1.5]      4 [1.5]      9 [1.6]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (47)         (50)                                   
      Fibrosis                                                                   1 [3.0]                                            
      Hyperplasia                                                   1 [3.0]                                                         
      Hyperplasia, Focal, Histiocytic                               1 [3.0]      1 [2.0]                                            
      Myeloid Cell, Hyperplasia                                     1 [3.0]                   5 [3.0]                               
   Lymph Node                                         (39)         (49)         (42)         (38)                                   
      Hemorrhage                                                                              1 [2.0]                               
      Hyperplasia, Lymphoid                                                      1 [3.0]                                            
      Mediastinal, Angiectasis                                      1 [3.0]                                                         
      Mediastinal, Congestion                                                    1 [4.0]                                            
      Mediastinal, Ectasia                             1 [3.0]                   3 [3.0]      1 [3.0]                               
      Mediastinal, Hemorrhage                          1 [3.0]      1 [3.0]      5 [3.0]      1 [3.0]                               
      Mediastinal, Hyperplasia, Histiocytic            2 [2.5]      1 [3.0]                   4 [2.8]                               
      Mediastinal, Hyperplasia, Lymphoid               1 [3.0]      1 [1.0]      1 [3.0]      1 [3.0]                               
      Mediastinal, Pigmentation                                     1 [3.0]                   1 [3.0]                               
      Pancreatic, Angiectasis                          1 [3.0]                                1 [3.0]                               
      Pancreatic, Ectasia                              1 [3.0]      3 [3.0]      3 [2.7]      2 [3.0]                               
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   14                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pancreatic, Hemorrhage                           1 [3.0]                   1 [2.0]      4 [2.8]                               
      Pancreatic, Hyperplasia, Focal, Histiocytic      1 [3.0]                                                                      
      Pancreatic, Hyperplasia, Histiocytic            13 [2.8]     12 [3.0]     15 [2.9]     19 [2.9]                               
      Pancreatic, Hyperplasia, Lymphoid                                          1 [3.0]      1 [2.0]                               
      Pancreatic, Pigmentation                         1 [3.0]                                1 [2.0]                               
   Lymph Node, Mandibular                             (2)          (1)          (2)          (2)                                    
      Hyperplasia, Plasma Cell                                                   1 [4.0]                                            
   Lymph Node, Mesenteric                             (47)         (50)         (50)         (50)                                   
      Ectasia                                                       2 [2.5]                   2 [3.0]                               
      Hemorrhage                                                                 1 [3.0]      1 [3.0]                               
      Hyperplasia, Histiocytic                         1 [3.0]      2 [3.0]      1 [3.0]      4 [2.8]                               
      Hyperplasia, Lymphoid                            2 [3.0]      1 [3.0]                                                         
   Spleen                                             (49)         (49)         (50)         (50)                                   
      Angiectasis, Focal                               1 [3.0]                   1 [2.0]                                            
      Congestion                                                                              1 [3.0]                               
      Cyst                                                          1                                                               
      Fibrosis, Focal                                  2 [2.5]                   2 [2.5]      1 [2.0]                               
      Hematopoietic Cell Proliferation                 4 [2.5]      4 [2.5]      1 [3.0]      6 [2.5]                               
      Hemorrhage                                                                 1 [3.0]                                            
      Hemorrhage, Focal                                                                       1 [3.0]                               
      Hyperplasia, Lymphoid                                         1 [2.0]      2 [2.5]                                            
      Infarct                                          1 [2.5]      1 [3.0]                                                         
      Inflammation, Granulomatous                                                2 [3.0]      3 [1.7]                               
      Necrosis, Focal                                  1 [4.0]                   1 [2.0]      1 [3.0]                               
      Pigmentation                                                               1 [2.0]                                            
      Capsule, Fibrosis, Focal                         1 [2.0]                                                                      
   Thymus                                             (48)         (48)         (44)         (49)                                   
      Atrophy                                          1 [3.0]      1 [3.0]                                                         
      Cyst, Multiple                                   1 [4.0]                                                                      
      Hemorrhage                                       1 [3.0]                                1 [2.0]                               
      Hyperplasia, Lymphoid                            2 [3.0]      1 [3.0]      1 [3.0]                                            
      Epithelial Cell, Cyst, Multiple                               1 [3.0]                                                         
      Epithelial Cell, Hyperplasia                     1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (48)         (47)         (45)         (42)                                   
      Dilatation                                       7 [2.1]      1 [2.0]      3 [2.3]      2 [2.5]                               
      Ectasia                                                                    1 [3.0]                                            
      Hyperplasia                                      2 [2.0]                                                                      
      Hyperplasia, Cystic                                                                     1 [3.0]                               
      Epithelium, Pigmentation                                      1 [2.0]                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   15                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
   Skin                                               (50)         (50)         (50)         (50)                                   
      Angiectasis, Focal                                            1 [1.0]                                                         
      Cyst Epithelial Inclusion                                                  1 [1.0]      1 [3.0]                               
      Fibrosis, Focal                                  1 [3.0]                                                                      
      Hemorrhage, Focal                                1 [2.0]                                1 [2.0]                               
      Inflammation, Chronic, Focal                     1 [2.0]                   1 [2.0]      1 [2.0]                               
      Necrosis, Focal                                                                         1 [2.0]                               
      Pinna, Necrosis, Focal                           1 [3.0]                                                                      
      Subcutaneous Tissue, Angiectasis, Focal                                                 1 [2.0]                               
      Subcutaneous Tissue, Cyst                                                               1 [2.0]                               
      Subcutaneous Tissue, Foreign Body                                                       1 [3.0]                               
      Subcutaneous Tissue, Hemorrhage, Focal                                                  1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (2)          (1)          (1)          (4)                                    
      Fibrosis, Focal                                                                         1 [1.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression, Focal                               4 [3.0]      2 [2.5]      4 [3.0]      1 [2.0]                               
      Hemorrhage, Focal                                2 [2.5]      3 [3.3]      2 [3.0]      1 [2.0]                               
      Necrosis, Focal                                  1 [3.0]      1 [3.0]                                                         
   Spinal Cord                                        (1)                       (1)                                                 
      Hemorrhage, Focal                                                          1 [3.0]                                            
      Mineralization, Focal                                                      1 [2.0]                                            
      Necrosis, Focal                                                            1 [3.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                                                       (1)          (1)                                    
      Glands, Hyperplasia, Focal                                                              1 [3.0]                               
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       1 [3.0]                   1 [3.0]      1 [2.0]                               
      Hemorrhage, Focal                                1 [2.0]                   1 [3.0]      1 [2.0]                               
      Hyperplasia, Focal, Histiocytic                  4 [2.3]      1 [2.0]                                                         
      Hyperplasia, Histiocytic                         3 [1.3]      3 [1.7]      2 [1.0]      2 [1.0]                               
      Infiltration Cellular, Focal, Mixed Cell                                                1 [3.0]                               
      Infiltration Cellular, Mixed Cell                2 [2.5]      1 [2.0]      1 [3.0]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   16                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Inflammation, Focal                                                                     1 [3.0]                               
      Metaplasia, Focal, Osseous                                    2 [1.5]      1 [1.0]      2 [1.0]                               
      Metaplasia, Osseous                                                                     2 [1.0]                               
      Alveolar Epithelium, Hyperplasia, Focal          2 [1.0]      9 [1.6]      6 [1.7]      5 [1.8]                               
      Alveolus, Foreign Body, Focal                                                           1 [2.0]                               
      Interstitium, Edema                                                        1 [2.0]      1 [2.0]                               
   Nose                                               (50)         (50)         (50)         (50)                                   
      Foreign Body                                     1 [2.0]                                                                      
      Inflammation, Suppurative                        2 [2.0]                   1 [2.0]                                            
      Nasolacrimal Duct, Inflammation                               2 [2.0]      1 [3.0]      2 [3.0]                               
      Nasolacrimal Duct, Inflammation, Chronic                      1 [2.0]                                                         
      Nasolacrimal Duct, Inflammation, Suppurative                  3 [2.3]                                                         
      Sinus, Foreign Body                                           1 [3.0]                                                         
      Sinus, Inflammation, Suppurative                              1 [3.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (49)         (50)         (46)         (50)                                   
      Atrophy                                                       1 [3.0]                                                         
      Cataract                                         1 [3.0]                   1 [2.0]                                            
      Synechia                                                                   1 [3.0]                                            
      Cornea, Inflammation, Focal                                   1 [2.0]                                                         
      Cornea, Necrosis, Focal                                       1 [1.0]                                                         
      Iris, Hyperplasia                                1 [2.0]                                                                      
      Lens, Cataract                                                1 [2.0]                                                         
      Retina, Degeneration                                                       1 [3.0]                                            
      Retrobulbar, Inflammation, Focal                              1 [2.0]                                                         
   Harderian Gland                                    (50)         (50)         (49)         (50)                                   
      Hyperplasia, Focal                                            1 [1.0]                   2 [1.0]                               
      Hyperplasia, Focal, Histiocytic                                                         1 [1.0]                               
      Hyperplasia, Histiocytic                                                   1 [2.0]                                            
      Inflammation, Chronic, Focal                     1 [1.0]                   2 [1.0]      3 [1.7]                               
      Inflammation, Focal, Granulomatous                                                      1 [1.0]                               
      Epithelium, Hyperplasia, Focal                   3 [1.3]                                1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (49)         (49)         (50)                                   
      Accumulation, Hyaline Droplet                    1 [3.0]                                                                      
      Atrophy, Focal                                                                          1 [2.0]                               
      Congestion                                       1 [2.0]      1 [3.0]                                                         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   17                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 03/14/03    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 10:45:10    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0PPM         300 PPM      1000 PPM     3000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Cyst                                                          2 [2.5]                   2 [2.0]                               
      Fibrosis, Focal                                                                         1 [2.0]                               
      Infarct                                                       1 [3.0]                                                         
      Inflammation                                     1 [2.0]                                                                      
      Nephropathy                                     43 [1.3]     43 [1.3]     41 [1.2]     46 [1.2]                               
      Pelvis, Inflammation, Chronic                                              1 [3.0]                                            
      Pelvis, Transitional Epithelium, Hyperplasia                               1 [3.0]                                            
      Renal Tubule, Accumulation, Hyaline Droplet      1 [3.0]      1 [1.0]      3 [3.0]      2 [3.0]                               
      Renal Tubule, Necrosis, Focal                    1 [2.0]                                                                      
      Renal Tubule, Pigmentation                       5 [2.8]      3 [2.0]      2 [2.5]      3 [2.3]                               
   Urinary Bladder                                    (50)         (50)         (49)         (50)                                   
      Hemorrhage                                                                 1 [3.0]                                            
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   18                                                              
                                                                                                                                   
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------