Skip to Main Navigation
Skip to Page Content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
https://ntp.niehs.nih.gov/go/3183

TDMS Study 92012-06 Pathology Tables

NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43

                                                   FINAL #1; REVISION #2 MICE




       Facility:  Southern Research Institute

       Chemical CAS #:  693-98-1

       Lock Date:  10/16/01

       Cage Range:  All

       Reasons For Removal:    25019 Moribund Sacrifice                25020 Natural Death
                               25026 Other                             25021 Terminal Sacrifice

       Removal Date Range:     All

       Treatment Groups:       Include All
































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

                                                              Page   1


NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 2            3            4            4                                     
    Natural Death                                      2            3            2            1                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                46           42           42           45                                     
    Moribund Sacrifice                                                           1                                                  
    Natural Death                                                   1                                                               
  Other                                                             1            1                                                  
                                                                                                                                    
  Animals Examined Microscopically                    50           49           49           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (48)         (48)         (50)                                   
      Edema                                            2 [2.0]                   2 [2.0]      2 [2.0]                               
   Intestine Small, Jejunum                           (50)         (46)         (48)         (49)                                   
      Hyperplasia, Lymphoid                                         1 [3.0]                   1 [3.0]                               
      Peyer's Patch, Infiltration Cellular,                                                                                         
        Polymorphonuclear                                                                     1 [3.0]                               
   Intestine Small, Ileum                             (47)         (49)         (47)         (48)                                   
      Hyperplasia, Lymphoid                            1 [3.0]                                                                      
      Peyer's Patch, Infiltration Cellular,                                                                                         
        Polymorphonuclear                                                                     1 [3.0]                               
   Liver                                              (50)         (49)         (49)         (50)                                   
      Angiectasis                                      1 [3.0]                                                                      
      Basophilic Focus                                              4            1            1                                     
      Clear Cell Focus                                 1                         1            4                                     
      Eosinophilic Focus                                                         1                                                  
      Hematopoietic Cell Proliferation                 3 [3.0]      3 [2.0]      5 [1.8]      3 [3.0]                               
      Hemorrhage                                                    1 [3.0]                                                         
      Hepatodiaphragmatic Nodule                                                 1            2                                     
      Hyperplasia, Lymphoid                            3 [2.0]      3 [2.3]                   6 [2.2]                               
      Infarct                                                       1 [3.0]                                                         
      Infiltration Cellular, Mixed Cell               13 [1.7]      5 [1.6]     12 [1.3]     10 [1.1]                               
      Mixed Cell Focus                                 4            1            3                                                  
      Necrosis, Focal                                  5 [1.6]      2 [1.0]      3 [2.7]      4 [3.3]                               
      Tension Lipidosis                                                          2                                                  
      Bile Duct, Hyperplasia                                        1 [3.0]                                                         
      Hepatocyte, Vacuolization Cytoplasmic                                      1 [3.0]                                            
      Kupffer Cell, Pigmentation                                    2 [4.0]                                                         
                                                                                                                                    
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: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Mesentery                                          (3)          (4)          (6)          (6)                                    
      Inflammation, Chronic                            1 [4.0]      1 [3.0]                                                         
      Fat, Angiectasis                                                           1 [3.0]      1 [3.0]                               
      Fat, Necrosis                                    2 [3.0]      3 [2.3]      6 [1.8]      6 [2.8]                               
   Pancreas                                           (50)         (49)         (48)         (50)                                   
      Atrophy                                          1 [4.0]                                                                      
      Cyst                                             1 [3.0]      1 [3.0]      1 [3.0]      2 [3.0]                               
      Acinus, Cytoplasmic Alteration                                             2 [3.0]      1 [3.0]                               
   Salivary Glands                                    (50)         (49)         (49)         (49)                                   
      Atrophy                                          2 [2.0]                                1 [1.0]                               
      Hyperplasia, Lymphoid                                         5 [2.6]      3 [2.0]      2 [2.0]                               
   Stomach, Forestomach                               (50)         (49)         (49)         (50)                                   
      Diverticulum                                     1                                      5                                     
      Inflammation, Chronic Active                     1 [2.0]      1 [2.0]      2 [2.5]                                            
      Epithelium, Hyperplasia                          1 [2.0]                   4 [2.5]      1 [1.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (49)         (49)         (50)                                   
      Cardiomyopathy                                                                          2 [1.0]                               
      Thrombosis                                                                              1 [3.0]                               
      Myocardium, Necrosis                                                       1 [2.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (49)         (50)                                   
      Accessory Adrenal Cortical Nodule                7 [3.0]      5 [3.0]      4 [3.0]      6 [3.0]                               
      Hyperplasia, Focal                                                                      2 [1.5]                               
      Capsule, Hyperplasia                             3 [2.0]                                                                      
   Adrenal Medulla                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia                                                                1 [2.0]                                            
   Islets, Pancreatic                                 (50)         (48)         (48)         (50)                                   
      Hyperplasia                                      1 [2.0]      1 [2.0]                   1 [2.0]                               
   Parathyroid Gland                                  (48)         (46)         (45)         (48)                                   
      Cyst                                                          1 [3.0]      1 [3.0]      1 [3.0]                               
   Pituitary Gland                                    (50)         (49)         (47)         (49)                                   
      Pars Distalis, Angiectasis                                    3 [2.3]      1 [2.0]      1 [2.0]                               
      Pars Distalis, Cyst                              1 [3.0]      3 [3.0]      1 [2.0]                                            
      Pars Distalis, Hyperplasia, Focal                1 [3.0]      2 [1.5]      1 [1.0]      2 [2.0]                               
   Thyroid Gland                                      (49)         (48)         (48)         (50)                                   
      Degeneration, Cystic                            15 [2.1]     14 [1.8]     12 [1.7]      9 [1.2]                               
                                                                                                                                    
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: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Follicle, Cyst                                                             1 [3.0]      1 [3.0]                               
      Follicular Cell, Hyperplasia                     1 [1.0]      1 [2.0]      1 [1.0]      9 [1.6]                               
      Follicular Cell, Hypertrophy                     6 [1.2]      3 [1.0]     23 [1.1]     46 [1.7]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (48)         (48)         (50)                                   
      Inflammation, Chronic                                                                   1 [4.0]                               
   Ovary                                              (50)         (49)         (49)         (48)                                   
      Angiectasis                                     12 [2.3]      7 [2.4]      8 [2.8]      8 [2.6]                               
      Cyst                                            10 [3.0]     11 [3.0]     15 [3.0]     10 [3.0]                               
      Inflammation, Chronic                            3 [4.0]                   2 [3.0]                                            
      Thrombosis                                                                              1 [4.0]                               
      Corpus Luteum, Hyperplasia                                                              1 [3.0]                               
   Uterus                                             (50)         (49)         (49)         (50)                                   
      Angiectasis                                      3 [3.3]      2 [2.5]      2 [3.5]      6 [2.2]                               
      Inflammation, Chronic                            6 [2.8]      2 [2.0]      9 [2.7]      4 [3.3]                               
      Metaplasia, Squamous                             5 [3.0]                   5 [3.0]      1 [3.0]                               
      Cervix, Cyst Epithelial Inclusion                             1                                                               
      Endometrium, Fibrosis                                                                   1 [3.0]                               
      Endometrium, Hyperplasia, Cystic                48 [3.0]     47 [3.1]     46 [3.3]     45 [3.4]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (48)         (50)                                   
      Hyperplasia                                     10 [2.7]      5 [2.0]     13 [3.2]     16 [2.4]                               
   Lymph Node                                         (12)         (6)          (8)          (9)                                    
      Bronchial, Hyperplasia, Lymphoid                 1 [3.0]                                2 [2.5]                               
      Iliac, Ectasia                                                             1 [3.0]                                            
      Iliac, Hematopoietic Cell Proliferation          2 [2.5]      1 [2.0]      1 [2.0]                                            
      Iliac, Hyperplasia, Lymphoid                     5 [2.2]      3 [3.0]      4 [3.0]      2 [4.0]                               
      Iliac, Pigmentation                                           1 [2.0]                                                         
      Inguinal, Hyperplasia, Lymphoid                                            1 [2.0]                                            
      Lumbar, Hyperplasia, Lymphoid                    1 [2.0]      1 [2.0]      2 [3.0]      2 [3.0]                               
      Lumbar, Pigmentation                                          1 [2.0]                                                         
      Mediastinal, Hyperplasia, Lymphoid               1 [4.0]      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    4                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Pancreatic, Hyperplasia, Lymphoid                                          1 [2.0]                                            
      Renal, Hematopoietic Cell Proliferation          1 [3.0]                   1 [2.0]                                            
      Renal, Hyperplasia, Lymphoid                     3 [2.7]      1 [4.0]      2 [2.5]                                            
   Lymph Node, Mandibular                             (48)         (48)         (46)         (48)                                   
      Atrophy                                                                    2 [2.5]                                            
      Hematopoietic Cell Proliferation                 3 [2.3]                                                                      
      Hemorrhage                                                                              1 [2.0]                               
      Hyperplasia, Lymphoid                           11 [2.0]     12 [1.8]     10 [2.0]     15 [1.7]                               
      Hyperplasia, Plasma Cell                         2 [2.0]      1 [3.0]      4 [1.8]                                            
      Pigmentation                                    24 [2.2]     20 [2.2]     21 [2.2]     21 [2.1]                               
   Lymph Node, Mesenteric                             (48)         (48)         (47)         (48)                                   
      Ectasia                                                                                 1 [2.0]                               
      Hematopoietic Cell Proliferation                 5 [2.2]      3 [2.3]                   3 [2.3]                               
      Hemorrhage                                                    1 [2.0]                   1 [2.0]                               
      Hyperplasia, Lymphoid                            3 [2.3]      7 [2.9]      4 [2.5]      6 [2.7]                               
      Hyperplasia, Plasma Cell                                      1 [3.0]                                                         
   Spleen                                             (50)         (49)         (49)         (50)                                   
      Angiectasis                                                                1 [2.0]                                            
      Atrophy                                                       1 [1.0]      1 [2.0]                                            
      Congestion                                       2 [2.0]                                                                      
      Hematopoietic Cell Proliferation                15 [2.1]     20 [2.2]     24 [2.5]     39 [2.4]                               
      Hyperplasia, Plasma Cell                                      1 [3.0]                                                         
      Pigmentation                                                  4 [1.3]     11 [1.5]     34 [1.7]                               
      Lymphoid Follicle, Atrophy                       1 [2.0]      3 [2.0]      5 [2.6]      4 [3.3]                               
      Lymphoid Follicle, Hyperplasia                  12 [1.8]     14 [1.8]     13 [2.3]     16 [2.2]                               
   Thymus                                             (50)         (48)         (48)         (50)                                   
      Atrophy                                          5 [2.6]      2 [2.0]      7 [3.1]      3 [3.0]                               
      Hyperplasia, Lymphoid                                                                   4 [2.5]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (49)         (49)         (50)                                   
      Hyperplasia                                                   2 [2.5]                   2 [1.0]                               
   Skin                                               (50)         (49)         (49)         (50)                                   
      Edema                                                                      1 [3.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (49)         (49)         (50)                                   
      Hyperostosis                                     9 [1.9]     13 [2.2]     10 [2.2]     11 [2.1]                               
   Skeletal Muscle                                                 (1)          (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    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
MUSCULOSKELETAL SYSTEM - CONT                                                                                                       
      Necrosis                                                                   1 [4.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (49)         (50)                                   
      Hemorrhage                                                    1 [1.0]      1 [2.0]                                            
      Inflammation, Chronic Active                                  1 [2.0]                                                         
      Vacuolization Cytoplasmic                                                               1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (49)         (49)         (50)                                   
      Edema                                            2 [2.0]                                1 [2.0]                               
      Foreign Body                                     2            2            2                                                  
      Hemorrhage                                       4 [1.3]      3 [1.3]      1 [2.0]      4 [1.5]                               
      Hyperplasia, Lymphoid                            9 [2.2]      6 [2.0]      3 [2.0]      7 [2.3]                               
      Infiltration Cellular, Histiocyte                2 [1.5]      2 [2.5]      3 [2.7]                                            
      Thrombosis                                                    1 [2.0]                   1 [1.0]                               
      Alveolar Epithelium, Hyperplasia                 1 [1.0]      2 [2.0]      3 [2.0]      2 [2.0]                               
   Nose                                               (50)         (49)         (49)         (50)                                   
      Foreign Body                                                  1                                                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (49)         (49)         (50)                                   
      Atrophy                                                                                 1 [4.0]                               
      Cataract                                                      1 [2.0]      2 [2.5]                                            
      Inflammation, Chronic                            1 [1.0]                   2 [2.5]                                            
   Harderian Gland                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia                                      1 [2.0]                                                                      
      Hyperplasia, Focal                                            3 [3.0]      2 [2.0]      1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (49)         (49)         (50)                                   
      Cyst                                             1 [3.0]      2 [3.0]      1 [3.0]      1 [3.0]                               
      Hyperplasia, Lymphoid                            8 [2.0]     16 [2.1]      8 [2.1]      4 [2.3]                               
      Infarct                                                                    2 [1.5]      2 [3.0]                               
      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    6                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                           0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Metaplasia, Osseous                                           1 [2.0]                   2 [2.5]                               
      Nephropathy                                     27 [1.1]     17 [1.1]     21 [1.1]     19 [1.0]                               
      Papilla, Necrosis                                                                       1 [3.0]                               
      Renal Tubule, Accumulation, Hyaline Droplet                   1 [2.0]                   1 [4.0]                               
      Renal Tubule, Dilatation                                                   1 [2.0]                                            
      Renal Tubule, Necrosis                                                     1 [3.0]      1 [2.0]                               
      Renal Tubule, Pigmentation                                    2 [2.5]                                                         
   Urinary Bladder                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia, Lymphoid                           16 [2.3]     16 [2.1]      6 [2.0]     11 [2.3]                               
      Inflammation, Chronic                            1 [1.0]      1 [2.0]                                                         
      Transitional Epithelium, Hyperplasia                          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    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          60           60           60           60                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 4            1            5            5                                     
    Natural Death                                      3            3            9            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                43           46           36           40                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (49)         (49)         (47)         (50)                                   
      Edema                                            2 [2.0]      1 [2.0]      1 [2.0]      1 [2.0]                               
   Intestine Small, Duodenum                          (49)         (49)         (45)         (50)                                   
      Epithelium, Hyperplasia                                                                 1 [3.0]                               
   Intestine Small, Jejunum                           (50)         (49)         (46)         (50)                                   
      Hyperplasia, Lymphoid                                         1 [2.0]      1 [3.0]                                            
      Infiltration Cellular, Polymorphonuclear                                   1 [3.0]                                            
   Intestine Small, Ileum                             (49)         (50)         (45)         (49)                                   
      Hyperplasia, Lymphoid                                         1 [2.0]                   1 [2.0]                               
      Infiltration Cellular, Polymorphonuclear                                                1 [2.0]                               
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 [3.0]                   1 [4.0]                                            
      Basophilic Focus                                 2            3            1            3                                     
      Clear Cell Focus                                 6            9            6            8                                     
      Cyst                                                          1 [3.0]                                                         
      Eosinophilic Focus                               3            3            2            6                                     
      Hematopoietic Cell Proliferation                 1 [3.0]                   2 [1.5]      2 [2.0]                               
      Hepatodiaphragmatic Nodule                                                              1                                     
      Infarct                                          1                                                                            
      Infiltration Cellular, Mixed Cell                5 [1.4]      7 [1.1]      7 [1.3]      7 [1.4]                               
      Mixed Cell Focus                                 4            3            4            4                                     
      Necrosis, Diffuse                                                                       1 [3.0]                               
      Necrosis, Focal                                  2 [2.0]      6 [1.5]      2 [2.5]      6 [2.2]                               
      Tension Lipidosis                                             2            1                                                  
      Hepatocyte, Cytoplasmic Alteration                                        11 [1.2]     37 [1.8]                               
      Hepatocyte, Karyomegaly                                                   10 [1.0]     29 [1.3]                               
      Hepatocyte, Vacuolization Cytoplasmic                         1 [3.0]                   1 [2.0]                               
      Kupffer Cell, Pigmentation                                    1 [3.0]      1 [2.0]     19 [1.5]                               
   Mesentery                                          (6)          (2)          (5)          (2)                                    
      Angiectasis                                                   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    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Inflammation, Chronic                                         1 [1.0]                                                         
      Fat, Necrosis                                    4 [2.3]      1 [2.0]      3 [2.3]      2 [2.5]                               
   Pancreas                                           (50)         (50)         (49)         (50)                                   
      Atrophy                                          1 [2.0]                   1 [4.0]                                            
      Cyst                                             2 [3.0]                   3 [3.0]      2 [3.0]                               
      Acinus, Cytoplasmic Alteration                                             2 [2.0]      1 [3.0]                               
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia, Lymphoid                            2 [2.0]      2 [2.0]                                                         
   Stomach, Forestomach                               (50)         (49)         (50)         (50)                                   
      Diverticulum                                                  2                                                               
      Inflammation, Chronic Active                     1 [2.0]      1 [1.0]                                                         
      Ulcer                                                         1 [3.0]                   1 [3.0]                               
      Epithelium, Hyperplasia                          2 [2.0]      2 [1.5]      1 [2.0]      1 [3.0]                               
   Stomach, Glandular                                 (50)         (49)         (49)         (50)                                   
      Glands, Dysplasia                                1 [3.0]                                                                      
   Tooth                                                                                     (1)                                    
      Inflammation, Chronic                                                                   1 [4.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   1 [1.0]                                1 [1.0]                               
      Perivascular, Inflammation, Chronic              3 [1.7]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                2 [3.0]      6 [3.0]      8 [3.0]      6 [3.0]                               
      Hyperplasia, Focal                               2 [1.5]      4 [1.5]      3 [1.3]      1 [1.0]                               
      Hypertrophy, Focal                              13 [1.3]     18 [1.6]     10 [1.2]     10 [1.7]                               
      Capsule, Hyperplasia                             1 [1.0]      2 [1.5]      3 [1.3]      2 [1.5]                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                                                2 [1.5]                                            
   Islets, Pancreatic                                 (50)         (50)         (49)         (50)                                   
      Hyperplasia                                                   2 [2.0]                   1 [2.0]                               
   Parathyroid Gland                                  (49)         (47)         (45)         (48)                                   
      Cyst                                             3 [3.0]      1 [3.0]      2 [3.0]      1 [3.0]                               
   Pituitary Gland                                    (49)         (48)         (48)         (50)                                   
      Pars Distalis, Cyst                              2 [3.0]      1 [3.0]      2 [3.0]      2 [3.0]                               
      Pars Distalis, Hyperplasia, Focal                             1 [4.0]                                                         
   Thyroid Gland                                      (50)         (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    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Degeneration, Cystic                            10 [2.0]      2 [1.0]      3 [2.0]      4 [1.5]                               
      Follicular Cell, Hyperplasia                                  2 [1.5]      3 [1.7]     33 [1.9]                               
      Follicular Cell, Hypertrophy                     1 [1.0]                   6 [1.2]     25 [1.3]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Fibrosis                                         1 [2.0]                                                                      
      Granuloma Sperm                                                            3 [2.7]      6 [2.5]                               
      Hyperplasia, Lymphoid                                                      2 [2.5]      1 [3.0]                               
      Hypospermia                                                                1 [4.0]                                            
      Inflammation, Chronic Active                     1 [1.0]      3 [1.3]      7 [2.0]      8 [2.9]                               
   Penis                                              (1)                       (1)          (1)                                    
      Angiectasis                                                                1 [3.0]      1 [3.0]                               
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Cyst                                            18 [3.0]     23 [3.0]     16 [3.0]     21 [3.0]                               
      Inflammation, Chronic                           14 [2.4]     10 [2.2]     14 [2.1]      7 [2.4]                               
   Prostate                                           (49)         (50)         (49)         (50)                                   
      Inflammation, Chronic                                                                   2 [2.5]                               
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 [2.0]                                                                      
   Testes                                             (50)         (50)         (50)         (50)                                   
      Germinal Epithelium, Atrophy                     1 [2.0]      4 [2.0]      8 [2.3]     14 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      4 [3.0]     10 [2.8]     20 [2.1]     42 [2.5]                               
   Lymph Node                                         (2)          (3)                       (1)                                    
      Bronchial, Hyperplasia, Lymphoid                              1 [2.0]                                                         
   Lymph Node, Mandibular                             (48)         (46)         (45)         (50)                                   
      Atrophy                                          1 [3.0]                   2 [2.0]      4 [2.8]                               
      Ectasia                                                                    1 [2.0]                                            
      Hyperplasia, Lymphoid                           10 [2.1]     14 [2.3]      9 [2.6]     13 [2.2]                               
      Pigmentation                                     8 [2.1]      6 [2.2]      9 [2.0]      6 [2.0]                               
   Lymph Node, Mesenteric                             (47)         (47)         (46)         (48)                                   
                                                                                                                                    
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: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Angiectasis                                                                             1 [3.0]                               
      Atrophy                                          1 [2.0]      1 [3.0]      2 [2.5]      2 [3.0]                               
      Hemorrhage                                       4 [1.8]      2 [1.5]      2 [2.0]                                            
      Hyperplasia, Lymphoid                            7 [2.4]      7 [2.1]     15 [2.4]     10 [2.3]                               
      Necrosis                                         1 [4.0]                                1 [3.0]                               
   Spleen                                             (50)         (50)         (49)         (50)                                   
      Angiectasis                                                                             1 [2.0]                               
      Atrophy                                                       1 [3.0]      4 [3.0]      3 [2.7]                               
      Hematopoietic Cell Proliferation                10 [2.2]     21 [2.3]     38 [2.5]     45 [2.9]                               
      Pigmentation                                     1 [2.0]     16 [1.1]     33 [1.6]     43 [2.2]                               
      Lymphoid Follicle, Atrophy                                    4 [3.3]     14 [1.6]     30 [1.8]                               
      Lymphoid Follicle, Hyperplasia                   5 [2.0]      2 [1.5]      2 [2.0]                                            
   Thymus                                             (47)         (46)         (46)         (47)                                   
      Atrophy                                          7 [2.6]      5 [2.2]      9 [3.4]      8 [3.1]                               
      Cyst                                             1 [3.0]                   1 [3.0]      1 [3.0]                               
      Hyperplasia, Lymphoid                                         1 [3.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Chronic                                         1 [4.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (1)          (1)                       (2)                                    
      Atrophy                                                                                 1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression                                                   1 [3.0]                                                         
   Peripheral Nerve                                   (1)                                    (1)                                    
      Atrophy                                                                                 1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Edema                                            1 [2.0]      3 [2.0]      1 [2.0]      3 [2.0]                               
      Hemorrhage                                       4 [2.0]      8 [1.5]      4 [1.8]      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   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92012-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 08/06/04    
Route: DOSED FEED                                             2-METHYLIMIDAZOLE                                   Time: 09:44:43    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                             0PPM         625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Hyperplasia, Lymphoid                            1 [2.0]      2 [2.0]      2 [2.0]      4 [2.0]                               
      Infiltration Cellular, Histiocyte                4 [2.8]      4 [3.0]      4 [2.0]      2 [3.0]                               
      Inflammation, Chronic                                                      1 [1.0]      2 [1.5]                               
      Metaplasia, Osseous                                                        2 [1.0]                                            
      Thrombosis                                       1 [1.0]                                1 [2.0]                               
      Alveolar Epithelium, Hyperplasia                 5 [3.2]      3 [2.0]      1 [1.0]      3 [2.3]                               
      Alveolar Epithelium, Hyperplasia, Multifocal     1 [3.0]                                                                      
   Nose                                               (50)         (50)         (50)         (50)                                   
      Foreign Body                                     1            3            3            2                                     
      Inflammation, Chronic                            1 [1.0]      4 [2.5]      3 [1.7]      2 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)         (50)         (50)         (50)                                   
      Cataract                                                                   1 [3.0]      1 [2.0]                               
      Inflammation, Chronic                            1 [3.0]      2 [3.0]      2 [2.0]      2 [3.0]                               
      Cornea, Hyperplasia                              1 [2.0]                   1 [2.0]                                            
   Harderian Gland                                    (50)         (50)         (48)         (50)                                   
      Hyperplasia, Focal                               1 [2.0]                   2 [2.5]                                            
      Inflammation, Chronic                            3 [1.7]      4 [1.8]                   2 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                            13 [3.0]     11 [3.0]     12 [3.0]     19 [3.0]                               
      Hydronephrosis                                   1 [2.0]                                                                      
      Hyperplasia, Lymphoid                            1 [2.0]      3 [2.0]      3 [2.0]      3 [2.0]                               
      Infarct                                          6 [1.8]      6 [1.8]      6 [2.2]      1 [2.0]                               
      Inflammation, Suppurative                                                               1 [4.0]                               
      Metaplasia, Osseous                              5 [1.8]      3 [1.3]      2 [1.0]      3 [1.7]                               
      Nephropathy                                     34 [1.2]     43 [1.5]     32 [1.5]     31 [1.1]                               
      Papilla, Necrosis                                                                       1 [2.0]                               
      Renal Tubule, Hyperplasia                        1 [1.0]      1 [1.0]      2 [1.0]      3 [1.7]                               
      Renal Tubule, Pigmentation                       1 [2.0]                   2 [1.5]     45 [2.5]                               
   Urethra                                                                                   (1)                                    
      Angiectasis                                                                             1 [4.0]                               
      Inflammation, Suppurative                                                               1 [3.0]                               
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Transitional Epithelium, Hyperplasia                                                    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   12                                                              
                                                                                                                                   
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------