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TDMS Study 92013-05 Pathology Tables

NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53

                                                         FINAL #1 RATS




       Facility:  Southern Research Institute

       Chemical CAS #:  822-36-6

       Lock Date:  09/13/02

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All

































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

                                                              Page   1


NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      2            6           11            6                                     
    Moribund Sacrifice                                 5            5            5            9                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                40           39           34           33                                     
    Natural Death                                      3                                      2                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (48)         (46)         (43)         (43)                                   
      Edema                                            1 [3.0]                                                                      
   Liver                                              (50)         (50)         (48)         (50)                                   
      Basophilic Focus                                46           43           31           25                                     
      Clear Cell Focus                                20           32           23           27                                     
      Congestion                                       2 [3.0]      2 [2.5]                   1 [3.0]                               
      Degeneration, Cystic, Focal                      1 [1.0]                   1 [3.0]      3 [3.0]                               
      Eosinophilic Focus                               1            2            5           11                                     
      Hematopoietic Cell Proliferation                 1 [3.0]                                                                      
      Hemorrhage                                                                              1 [2.0]                               
      Hepatodiaphragmatic Nodule                       5            4            6           11                                     
      Histiocytosis                                   40 [1.0]     50 [1.3]     48 [1.9]     50 [2.5]                               
      Hyperplasia, Focal, Histiocytic                                                         2 [2.0]                               
      Infiltration Cellular, Mixed Cell                5 [1.0]      5 [1.4]                   5 [1.6]                               
      Inflammation, Chronic                           17 [1.2]     28 [1.5]     34 [1.8]     35 [1.7]                               
      Inflammation, Chronic, Focal                                               1 [1.0]                                            
      Inflammation, Granulomatous                      1 [1.0]                                                                      
      Mixed Cell Focus                                10            7            6           18                                     
      Thrombosis                                                                 1 [2.0]                                            
      Bile Duct, Cyst                                                                         1                                     
      Bile Duct, Dilatation, Focal                                               2 [2.5]      1 [2.0]                               
      Bile Duct, Hyperplasia                          31 [1.5]     38 [1.6]     43 [1.9]     35 [1.9]                               
      Hepatocyte, Fatty Change, Focal                 16 [1.2]     29 [1.6]     29 [2.0]     32 [2.2]                               
      Hepatocyte, Hyperplasia, Focal                   1 [3.0]                                                                      
      Hepatocyte, Necrosis, Focal                      1 [2.0]                                1 [2.0]                               
      Hepatocyte, Vacuolization Cytoplasmic            6 [2.7]     12 [2.3]     17 [2.4]     11 [2.4]                               
      Hepatocyte, Centrilobular, Necrosis              2 [3.0]                   1 [3.0]      1 [4.0]                               
      Oval Cell, Hyperplasia, Focal                    1 [2.0]                                2 [2.0]                               
      Serosa, Fibrosis                                                           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: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Mesentery                                          (9)          (7)          (11)         (8)                                    
      Inflammation, Chronic                            1 [3.0]                   1 [1.0]                                            
      Fat, Necrosis, Focal                             8 [2.5]      3 [2.0]                   1 [1.0]                               
      Lymphatic, Angiectasis                                                                  1 [2.0]                               
   Pancreas                                           (49)         (49)         (47)         (47)                                   
      Acinus, Atrophy, Diffuse                         1 [4.0]                                                                      
      Acinus, Atrophy, Focal                          13 [1.3]     22 [1.7]     26 [1.8]     30 [1.7]                               
      Duct, Cyst, Focal, Multiple                     10 [1.5]     18 [2.0]     11 [1.4]      9 [1.7]                               
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy, Focal                                                             2 [1.5]                                            
      Inflammation, Chronic                                         1 [4.0]      1 [3.0]      1 [3.0]                               
   Stomach, Forestomach                               (50)         (50)         (49)         (50)                                   
      Diverticulum                                                               1                                                  
      Edema                                            1 [3.0]      1 [3.0]      2 [3.0]      1 [3.0]                               
      Inflammation                                                               2 [2.0]                                            
      Ulcer                                            1 [1.0]      1 [2.0]      3 [1.7]      2 [1.0]                               
      Epithelium, Hyperplasia                                       1 [2.0]      6 [2.0]      1 [1.0]                               
   Stomach, Glandular                                 (50)         (50)         (49)         (49)                                   
      Erosion                                          2 [2.0]      1 [2.0]      1 [3.0]      4 [1.5]                               
      Ulcer                                                         1 [2.0]                                                         
   Tongue                                                          (5)          (4)          (3)                                    
      Epithelium, Hyperplasia                                       1 [2.0]      1 [1.0]                                            
   Tooth                                              (1)          (1)          (2)                                                 
      Malformation                                                  1 [2.0]      2 [2.0]                                            
      Peridontal Tissue, Inflammation                  1 [4.0]      1 [3.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (48)         (50)                                   
      Cardiomyopathy                                  30 [1.3]     43 [1.5]     38 [1.8]     44 [1.9]                               
      Inflammation, Focal, Suppurative                              1 [2.0]                                                         
      Thrombosis                                                                 2 [3.0]      5 [3.4]                               
      Artery, Inflammation, Chronic                                              1 [2.0]                                            
      Epicardium, Inflammation                         1 [3.0]                                                                      
      Myocardium, Fibrosis, Focal                      1 [2.0]                                                                      
      Pericardium, Infiltration Cellular, Mixed                                                                                     
        Cell                                           1 [1.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (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    3                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Accessory Adrenal Cortical Nodule                8 [1.3]      6 [1.2]      3 [1.3]      2 [1.0]                               
      Angiectasis                                      4 [2.5]      2 [2.5]      7 [2.6]      4 [2.8]                               
      Cytoplasmic Alteration, Focal                    1 [2.0]      2 [1.0]      2 [1.5]      2 [2.0]                               
      Hematopoietic Cell Proliferation                              1 [1.0]                                                         
      Hemorrhage, Focal                                                          2 [3.0]      1 [3.0]                               
      Vacuolization Cytoplasmic, Focal                 8 [2.3]      9 [2.0]     13 [2.2]     12 [1.6]                               
   Adrenal Medulla                                    (48)         (50)         (50)         (50)                                   
      Angiectasis                                      1 [2.0]                                1 [2.0]                               
      Atrophy                                                                    1 [3.0]                                            
      Hyperplasia, Focal                               2 [1.0]                   2 [2.5]                                            
      Hyperplasia, Lymphoid                                         1 [3.0]                                                         
   Islets, Pancreatic                                 (49)         (50)         (48)         (47)                                   
      Atrophy                                                                    1 [3.0]                                            
   Parathyroid Gland                                  (50)         (49)         (48)         (49)                                   
      Hyperplasia, Focal                                                                      1 [2.0]                               
   Pituitary Gland                                    (48)         (50)         (50)         (50)                                   
      Angiectasis                                      6 [2.8]      4 [2.3]      3 [2.0]      4 [2.5]                               
      Cyst                                                          4            2            5                                     
      Hyperplasia, Focal, Histiocytic                               1 [2.0]                                                         
      Pars Distalis, Angiectasis                       1 [3.0]      2 [1.0]      3 [2.0]                                            
      Pars Distalis, Degeneration, Cystic, Focal       9 [1.9]      6 [2.5]      5 [1.8]      3 [1.7]                               
      Pars Distalis, Hemorrhage, Focal                                           1 [2.0]                                            
      Pars Distalis, Hyperplasia, Focal                4 [1.8]      4 [2.3]      5 [2.4]      4 [2.0]                               
      Pars Distalis, Hypertrophy, Focal                1 [3.0]                   1 [2.0]      4 [1.5]                               
   Thyroid Gland                                      (47)         (44)         (40)         (45)                                   
      C-Cell, Hyperplasia                             45 [2.0]     42 [1.7]     36 [1.9]     35 [1.7]                               
      Follicle, Cyst                                                1                                                               
      Follicle, Degeneration, Focal                                              1 [1.0]      1 [1.0]                               
      Follicle, Mineralization                         2 [1.0]      7 [1.0]      6 [1.0]     19 [1.0]                               
      Follicular Cell, Hyperplasia, Focal              1 [2.0]      1 [2.0]      1 [2.0]      2 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (5)          (3)          (6)          (6)                                    
      Fibrosis, Focal                                  1 [2.0]                                                                      
      Mediastinum, Cyst                                1 [2.0]                                                                      
      Mediastinum, Infiltration Cellular, Mixed                                                                                     
        Cell                                           1 [1.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
                                                                                                                                    
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: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
   Clitoral Gland                                     (50)         (50)         (50)         (50)                                   
      Degeneration, Cystic                             4 [2.3]                   5 [3.0]      3 [2.3]                               
      Hyperplasia, Cystic                              7 [2.4]      4 [2.3]      1 [2.0]      1 [3.0]                               
      Hyperplasia, Focal, Histiocytic                                            1 [2.0]                                            
      Inflammation, Chronic                            2 [2.0]      2 [1.5]                   3 [1.7]                               
   Ovary                                              (50)         (50)         (48)         (50)                                   
      Angiectasis                                                                             2 [3.0]                               
      Cyst                                             7            3            5                                                  
      Periovarian Tissue, Hemorrhage                                                          1 [3.0]                               
   Uterus                                             (50)         (50)         (48)         (50)                                   
      Inflammation, Chronic, Granulomatous             1 [3.0]                                                                      
      Ulcer                                                                      1 [4.0]                                            
      Cervix, Hypertrophy                              1 [3.0]                                                                      
      Endometrium, Hyperplasia, Cystic                25 [1.5]     26 [1.9]     18 [2.1]     26 [1.5]                               
   Vagina                                             (1)          (2)          (5)          (4)                                    
      Angiectasis                                                                             1 [3.0]                               
      Infiltration Cellular, Polymorphonuclear                      1 [2.0]                   1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (48)         (49)         (48)                                   
      Atrophy                                                                                 2 [3.0]                               
      Fibrosis                                                      1 [3.0]      1 [3.0]                                            
      Hyperplasia                                      3 [3.0]      2 [3.0]      1 [3.0]      2 [2.5]                               
      Hyperplasia, Focal, Histiocytic                               1 [2.0]      2 [2.0]      3 [2.0]                               
      Erythroid Cell, Hyperplasia                                   1 [3.0]                                                         
   Lymph Node                                         (24)         (11)         (24)         (35)                                   
      Hyperplasia, Plasma Cell                                                                1 [3.0]                               
      Deep Cervical, Hemorrhage                        3 [3.0]                                                                      
      Mediastinal, Congestion                                       1 [3.0]                                                         
      Mediastinal, Ectasia                             3 [3.3]      1 [3.0]                   1 [3.0]                               
      Mediastinal, Hemorrhage                          5 [3.0]      3 [2.7]      5 [3.0]      3 [3.0]                               
      Mediastinal, Hyperplasia, Histiocytic            4 [3.0]      1 [3.0]      1 [3.0]      6 [3.0]                               
      Mediastinal, Hyperplasia, Lymphoid               1 [3.0]                                1 [3.0]                               
      Mediastinal, Hyperplasia, Plasma Cell                                      1 [3.0]                                            
      Mediastinal, Pigmentation                        1 [3.0]                                                                      
      Pancreatic, Hemorrhage                           1 [2.0]                   2 [2.5]      2 [3.0]                               
      Pancreatic, Hyperplasia, Histiocytic             6 [2.8]      1 [3.0]      7 [3.0]      7 [3.1]                               
      Pancreatic, Hyperplasia, Lymphoid                                                       1 [3.0]                               
      Pancreatic, Hyperplasia, Plasma Cell             1 [3.0]                                                                      
      Pancreatic, Pigmentation                         1 [2.0]                                                                      
      Renal, Hyperplasia, Histiocytic                                                         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    5                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
   Lymph Node, Mandibular                             (1)          (3)          (1)          (4)                                    
      Ectasia                                                       1 [3.0]                                                         
      Hyperplasia, Histiocytic                                                                1 [3.0]                               
      Hyperplasia, Lymphoid                                                      1 [3.0]                                            
   Lymph Node, Mesenteric                             (49)         (49)         (49)         (47)                                   
      Ectasia                                                                    2 [3.0]                                            
      Hemorrhage                                                                              1 [3.0]                               
      Hyperplasia, Histiocytic                         7 [3.0]                   1 [3.0]      2 [3.0]                               
      Hyperplasia, Lymphoid                                                                   1 [3.0]                               
   Spleen                                             (50)         (48)         (47)         (48)                                   
      Accessory Spleen                                 3                         1            1                                     
      Atrophy                                                                    2 [2.5]                                            
      Congestion                                                                 1 [3.0]                                            
      Fibrosis, Focal                                  1 [3.0]                   1 [3.0]      1 [2.0]                               
      Hematopoietic Cell Proliferation                 6 [3.0]      2 [2.5]                                                         
      Inflammation, Granulomatous                                   3 [2.7]     10 [3.2]      3 [1.7]                               
      Stromal Hyperplasia                                           1 [3.0]                                                         
      Capsule, Infiltration Cellular, Focal, Mixed                                                                                  
        Cell                                                                     2 [2.0]      1 [1.0]                               
   Thymus                                             (47)         (50)         (48)         (48)                                   
      Angiectasis                                                                1 [2.0]                                            
      Cyst                                             2 [2.5]                                                                      
      Hemorrhage                                                    1 [3.0]                                                         
      Hyperplasia, Lymphoid                            1 [4.0]                   1 [2.0]      1 [3.0]                               
      Epithelial Cell, Hyperplasia                     1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (49)         (50)         (50)                                   
      Dilatation                                      37 [2.7]     16 [2.3]      8 [2.0]      1 [2.0]                               
      Fibrosis                                         1 [3.0]                                                                      
      Hyperplasia                                      6 [2.5]      3 [1.7]      3 [1.7]      1 [2.0]                               
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Focal                                                        1 [2.0]                                            
      Ulcer                                            1 [2.0]      1 [3.0]                   1 [3.0]                               
      Epidermis, Hyperplasia, Focal                                              1 [1.0]      2 [2.5]                               
      Lip, Cyst Epithelial Inclusion                                                          1 [2.0]                               
      Pinna, Inflammation, Chronic, Focal                           1 [2.0]                                                         
      Subcutaneous Tissue, Edema                       1 [3.0]      1 [2.0]                   1 [3.0]                               
      Subcutaneous Tissue, Fibrosis, Focal                          1 [2.0]                                                         
      Subcutaneous Tissue, Hemorrhage, Focal                                     1 [2.0]                                            
      Subcutaneous Tissue, Necrosis, Fatty, Focal                                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: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression, Focal                              13 [2.8]      8 [3.0]      8 [3.0]      2 [2.5]                               
      Hemorrhage, Focal                                1 [2.0]      2 [3.0]      4 [2.0]      2 [1.5]                               
      Meninges, Hemorrhage, Focal                                                             1 [3.0]                               
      Thalamus, Mineralization, Focal                                            1 [2.0]      1 [2.0]                               
   Spinal Cord                                        (7)          (3)          (24)         (50)                                   
      Hemorrhage, Focal                                                                       2 [3.0]                               
      Necrosis, Focal                                                                         1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       1 [2.0]      5 [2.2]      3 [3.0]      5 [2.2]                               
      Hemorrhage, Focal                                1 [3.0]                   2 [3.0]      2 [2.0]                               
      Hyperplasia, Focal, Histiocytic                               1 [2.0]                   2 [3.0]                               
      Infiltration Cellular, Mixed Cell                3 [1.7]      1 [1.0]                   1 [3.0]                               
      Inflammation, Chronic, Focal                    25 [1.1]     40 [1.2]     39 [1.0]     43 [1.2]                               
      Alveolar Epithelium, Hyperplasia, Focal          4 [2.0]      3 [1.3]                   2 [1.5]                               
      Interstitium, Edema                              1 [2.0]                   1 [2.0]                                            
      Mediastinum, Congestion                                                    1 [3.0]                                            
      Mediastinum, Edema                               1 [2.0]      1 [2.0]      1 [3.0]                                            
      Mediastinum, Mineralization, Focal                                         1 [3.0]                                            
   Nose                                               (49)         (50)         (50)         (50)                                   
      Foreign Body                                                  2 [1.5]                                                         
      Inflammation, Suppurative                                     3 [2.0]      1 [2.0]                                            
      Nasolacrimal Duct, Hemorrhage                                                           1 [1.0]                               
      Nasolacrimal Duct, Inflammation                  2 [2.5]      5 [2.0]      4 [2.0]      5 [2.6]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (48)         (45)         (40)         (45)                                   
      Atrophy                                                                    3 [3.3]      4 [3.3]                               
      Cataract                                         4 [2.8]                   1 [2.0]      1 [3.0]                               
      Inflammation, Chronic                                         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    7                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                      0 PPM        1250 PPM     2500 PPM     5000 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
SPECIAL SENSES SYSTEM - CONT                                                                                                        
      Synechia                                         1 [3.0]                                2 [3.0]                               
      Anterior Chamber, Exudate                                     1 [3.0]                   1 [3.0]                               
      Cornea, Inflammation, Chronic                                 1 [4.0]                                                         
      Cornea, Necrosis, Focal                                       1 [4.0]      1 [4.0]      2 [3.5]                               
      Retina, Degeneration                             4 [3.0]      1 [3.0]                   3 [3.0]                               
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Cytoplasmic Alteration, Focal                                              1 [1.0]                                            
      Hyperplasia, Focal, Histiocytic                  1 [1.0]      4 [1.5]      5 [1.2]                                            
      Inflammation                                     1 [1.0]      1 [1.0]                                                         
      Epithelium, Hyperplasia, Focal                                             1 [1.0]                                            
   Zymbal's Gland                                                  (3)          (1)                                                 
      Cyst                                                          1 [4.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (48)         (48)         (43)         (43)                                   
      Cyst                                                                       2 [2.5]                                            
      Hydronephrosis                                                                          1 [2.0]                               
      Infarct                                          1 [2.0]      1 [2.0]      1 [4.0]      2 [2.0]                               
      Mineralization, Focal                                         1 [2.0]                                                         
      Nephropathy                                     45 [1.1]     37 [1.1]     36 [1.1]     38 [1.4]                               
      Pelvis, Dilatation                               1 [3.0]                                                                      
      Renal Tubule, Accumulation, Hyaline Droplet      3 [2.7]                   2 [2.5]      1 [3.0]                               
      Renal Tubule, Hyperplasia, Focal                                                        1 [2.0]                               
      Renal Tubule, Pigmentation                                                              2 [3.0]                               
   Urinary Bladder                                    (49)         (50)         (49)         (48)                                   
      Hemorrhage                                                                 1 [1.0]      2 [3.0]                               
      Inflammation                                                               1 [3.0]      1 [2.0]                               
      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    8                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                13           11           12           10                                     
    Natural Death                                      6            5            5            8                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                31           34           33           32                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (46)         (46)         (46)         (46)                                   
      Congestion                                                    1 [3.0]                                                         
      Edema                                                                                   1 [3.0]                               
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis, Focal                                            1 [2.0]                                                         
      Atrophy, Focal                                                             1 [2.0]                                            
      Basophilic Focus                                31           26           30           36                                     
      Clear Cell Focus                                31           28           29           31                                     
      Congestion                                       2 [2.0]                                                                      
      Degeneration, Cystic, Focal                      4 [1.3]      3 [1.3]      1 [2.0]      7 [2.0]                               
      Eosinophilic Focus                               4            3            7           12                                     
      Fibrosis                                         1 [2.0]                                                                      
      Hepatodiaphragmatic Nodule                       5            2            5            4                                     
      Histiocytosis                                   38 [1.1]     45 [1.4]     50 [1.9]     50 [2.3]                               
      Hyperplasia, Focal, Histiocytic                  1 [1.0]                   1 [2.0]      3 [2.0]                               
      Infiltration Cellular, Mixed Cell               15 [1.2]      5 [1.2]      5 [1.6]     17 [1.1]                               
      Inflammation, Chronic                           18 [1.1]     32 [1.2]     31 [1.3]     36 [1.3]                               
      Inflammation, Granulomatous                      1 [1.0]                                                                      
      Mixed Cell Focus                                 5            7           11           27                                     
      Thrombosis                                                                 1 [3.0]                                            
      Bile Duct, Dilatation, Focal                     2 [1.5]      2 [2.0]      2 [1.5]      2 [1.5]                               
      Bile Duct, Hyperplasia                          48 [2.8]     48 [2.9]     49 [2.9]     42 [3.0]                               
      Hepatocyte, Fatty Change, Focal                 21 [1.5]     24 [1.8]     37 [1.9]     33 [2.5]                               
      Hepatocyte, Necrosis, Focal                                   2 [2.0]      1 [2.0]                                            
      Hepatocyte, Vacuolization Cytoplasmic           11 [2.2]     14 [2.9]     12 [2.3]     18 [2.3]                               
      Serosa, Inflammation, Chronic, Focal             1 [2.0]                                                                      
   Mesentery                                          (13)         (10)         (11)         (10)                                   
      Inflammation, Chronic                                                      1 [2.0]      1 [3.0]                               
      Artery, Thrombosis                                                                      1 [3.0]                               
      Fat, Hemorrhage, 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    9                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Fat, Necrosis, Focal                             9 [2.8]      4 [3.0]      6 [3.0]      5 [2.8]                               
   Oral Mucosa                                        (1)          (1)          (1)                                                 
      Foreign Body                                                  1 [3.0]                                                         
      Hyperplasia, Focal, Squamous                                               1 [2.0]                                            
      Inflammation, Chronic, Focal                                  1 [3.0]                                                         
   Pancreas                                           (50)         (48)         (48)         (49)                                   
      Angiectasis                                                                1 [3.0]                                            
      Inflammation, Chronic                                                                   1 [3.0]                               
      Acinus, Atrophy, Diffuse                                                   1 [3.0]                                            
      Acinus, Atrophy, Focal                          23 [1.7]     24 [1.7]     24 [2.1]     25 [1.9]                               
      Duct, Cyst, Focal, Multiple                     15 [1.7]     12 [1.8]     16 [1.9]     10 [1.9]                               
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy, Focal                                   1 [2.0]                                                                      
      Inflammation, Chronic                                         1 [2.0]                                                         
   Stomach, Forestomach                               (50)         (50)         (50)         (49)                                   
      Diverticulum                                                                            1 [2.0]                               
      Edema                                            3 [3.0]                                                                      
      Hyperkeratosis, Focal                                         1 [2.0]                                                         
      Inflammation                                     1 [2.0]                   1 [2.0]      3 [2.0]                               
      Ulcer                                            5 [2.0]      2 [3.0]      2 [2.5]      3 [2.3]                               
      Epithelium, Hyperplasia                          4 [2.5]      3 [2.7]      2 [2.0]      4 [1.8]                               
   Stomach, Glandular                                 (50)         (50)         (49)         (49)                                   
      Cyst                                                                                    1 [2.0]                               
      Edema                                            2 [2.5]                                                                      
      Erosion                                          3 [1.7]      1 [2.0]      1 [1.0]      6 [1.8]                               
      Hyperplasia, Focal, Histiocytic                                            1 [1.0]                                            
      Inflammation, Focal                                           1 [2.0]                                                         
      Ulcer                                            1 [2.0]      1 [3.0]      2 [2.5]                                            
      Epithelium, Hyperplasia                                                    1 [2.0]                                            
   Tongue                                                          (3)          (1)          (1)                                    
      Epithelium, Cyst                                              1 [2.0]                                                         
      Epithelium, Hyperplasia                                                    1 [1.0]      1 [1.0]                               
   Tooth                                              (1)          (1)                                                              
      Peridontal Tissue, Inflammation                  1 [3.0]      1 [3.0]                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  40 [1.7]     38 [1.7]     36 [1.6]     39 [1.8]                               
      Thrombosis                                       1 [4.0]      3 [3.0]      1 [3.0]      4 [2.8]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
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: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Accessory Adrenal Cortical Nodule                9 [1.2]      6 [1.2]      5 [1.2]      9 [1.0]                               
      Angiectasis                                                   1 [2.0]                                                         
      Cytoplasmic Alteration, Focal                    3 [1.0]      2 [1.5]      1 [2.0]      2 [1.0]                               
      Degeneration, Cystic                                          1 [4.0]                                                         
      Hematopoietic Cell Proliferation                 1 [3.0]                                                                      
      Hemorrhage, Focal                                1 [2.0]                                                                      
      Hyperplasia, Focal                                                                      1 [1.0]                               
      Necrosis                                         1 [2.0]      1 [4.0]      1 [2.0]                                            
      Vacuolization Cytoplasmic, Focal                 6 [1.3]      5 [1.4]     13 [1.4]      7 [1.3]                               
      Capsule, Hyperplasia, Focal                                                             1 [2.0]                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia, Focal                               7 [1.4]      1 [1.0]      3 [1.3]                                            
      Necrosis                                                      1 [3.0]                                                         
   Islets, Pancreatic                                 (50)         (49)         (49)         (49)                                   
      Hyperplasia                                      1 [2.0]                                1 [2.0]                               
   Parathyroid Gland                                  (48)         (50)         (48)         (50)                                   
      Hyperplasia, Focal                               1 [2.0]                                2 [2.5]                               
   Pituitary Gland                                    (49)         (49)         (48)         (48)                                   
      Angiectasis                                      1 [2.0]                   4 [2.5]      1 [3.0]                               
      Cyst                                             4            2            6            1                                     
      Fibrosis, Focal                                                                         1 [3.0]                               
      Hemorrhage                                                                              1 [3.0]                               
      Pars Distalis, Cytoplasmic Alteration, Focal                               2 [1.5]                                            
      Pars Distalis, Degeneration, Cystic, Focal                    1 [2.0]                                                         
      Pars Distalis, Hemorrhage, Focal                 2 [2.5]                                                                      
      Pars Distalis, Hyperplasia                       1 [3.0]                                                                      
      Pars Distalis, Hyperplasia, Focal                3 [2.3]      1 [2.0]      1 [2.0]      1 [2.0]                               
      Pars Distalis, Hypertrophy, Focal                8 [1.8]      9 [1.6]     20 [1.8]     22 [2.0]                               
      Pars Nervosa, Inflammation                       1 [1.0]                                                                      
   Thyroid Gland                                      (47)         (46)         (48)         (44)                                   
      C-Cell, Hyperplasia                             41 [1.5]     28 [1.6]     26 [1.5]     29 [1.7]                               
      Follicle, Cyst                                                3            1            5                                     
      Follicle, Degeneration, Focal                    6 [1.0]      4 [1.5]      8 [1.3]      4 [1.3]                               
      Follicle, Mineralization                         3 [1.0]      3 [1.0]      5 [1.0]      6 [1.0]                               
      Follicular Cell, Hyperplasia, Focal              1 [1.0]      1 [1.0]      1 [2.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Peritoneum                                                      (2)          (3)          (1)                                    
      Inflammation, Chronic, 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   11                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENERAL BODY SYSTEM - CONT                                                                                                          
   Tissue NOS                                         (6)          (4)          (6)          (5)                                    
      Inflammation, Chronic                                                                   1 [3.0]                               
      Mediastinum, Cyst                                1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                                                         (1)                                    
      Inflammation, Chronic                                                                   1 [2.0]                               
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  1 [3.0]                                1 [3.0]                               
      Hemorrhage                                                                              1 [3.0]                               
      Inflammation, Chronic                                                      1 [2.0]                                            
      Spermatocele                                     1 [3.0]                                                                      
   Preputial Gland                                    (50)         (50)         (50)         (49)                                   
      Degeneration, Cystic                             5 [2.8]      3 [2.7]      2 [2.5]      3 [2.7]                               
      Fibrosis                                         1 [3.0]                                                                      
      Hyperplasia, Cystic                              3 [2.3]      1 [2.0]                                                         
      Inflammation, Chronic                           30 [1.6]     28 [1.6]     21 [1.9]     23 [1.7]                               
   Prostate                                           (50)         (50)         (50)         (49)                                   
      Inflammation, Chronic                           27 [1.7]     24 [2.0]     28 [1.6]     36 [2.0]                               
      Epithelium, Hyperplasia, Focal                   4 [1.3]      6 [1.3]      5 [1.2]                                            
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Dilatation                                                                              1 [3.0]                               
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                         15 [3.0]     10 [2.8]      8 [3.0]     10 [3.1]                               
      Cyst                                             1 [3.0]                                                                      
      Interstitial Cell, Hyperplasia, Focal            4 [1.8]                   6 [1.8]      7 [1.6]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (47)         (50)         (48)         (50)                                   
      Angiectasis                                      1 [3.0]                                                                      
      Atrophy                                          1 [3.0]                                                                      
      Hyperplasia                                      2 [3.0]      3 [2.7]      2 [3.0]      4 [2.5]                               
   Lymph Node                                         (19)         (18)         (26)         (27)                                   
      Hyperplasia, Plasma Cell                                      1 [3.0]                                                         
      Deep Cervical, Hyperplasia, Histiocytic                                    1 [3.0]                                            
      Deep Cervical, Hyperplasia, Plasma Cell          1 [3.0]                                                                      
      Mediastinal, Ectasia                             2 [3.0]      2 [2.0]                   3 [3.0]                               
      Mediastinal, Hemorrhage                          3 [3.0]      2 [3.0]      2 [3.0]      3 [3.0]                               
      Mediastinal, Hyperplasia                                      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: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Mediastinal, Hyperplasia, Histiocytic            5 [3.0]                   2 [3.0]      3 [3.0]                               
      Mediastinal, Hyperplasia, Plasma Cell            2 [3.0]      2 [4.0]      2 [3.0]      1 [3.0]                               
      Pancreatic, Ectasia                              1 [2.0]                                                                      
      Pancreatic, Fibrosis                                                                    1 [3.0]                               
      Pancreatic, Hemorrhage                                        1 [3.0]      3 [2.3]      1 [3.0]                               
      Pancreatic, Hyperplasia, Histiocytic             2 [2.5]                   1 [3.0]      4 [3.0]                               
   Lymph Node, Mesenteric                             (50)         (48)         (48)         (49)                                   
      Ectasia                                          1 [3.0]      1 [3.0]                                                         
      Hemorrhage                                                                              1 [3.0]                               
      Hyperplasia, Histiocytic                         2 [3.0]      1 [3.0]                   2 [3.0]                               
      Hyperplasia, Lymphoid                                                                   1 [2.0]                               
   Spleen                                             (50)         (48)         (48)         (49)                                   
      Accessory Spleen                                 3                         1            3                                     
      Atrophy                                          3 [2.3]                                                                      
      Fibrosis, Diffuse                                1 [3.0]                                                                      
      Fibrosis, Focal                                  2 [3.0]      2 [3.0]      2 [3.0]                                            
      Hematopoietic Cell Proliferation                 1 [3.0]      1 [3.0]      1 [2.0]      1 [2.0]                               
      Hemorrhage                                       1 [4.0]                   1 [3.0]                                            
      Hyperplasia, Lymphoid                            1 [2.0]                                1 [3.0]                               
      Infarct                                                       1 [3.0]                   2 [3.0]                               
      Inflammation, Granulomatous                                   2 [3.0]      1 [1.0]      2 [2.0]                               
   Thymus                                             (48)         (49)         (46)         (45)                                   
      Angiectasis                                                                1 [3.0]                                            
      Hemorrhage                                       2 [2.5]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (47)         (46)         (41)         (45)                                   
      Dilatation                                      12 [2.3]      7 [2.6]      1 [2.0]      2 [3.0]                               
      Fibrosis                                         1 [2.0]                                1 [3.0]                               
      Inflammation, Chronic, Focal                                  1 [2.0]                                                         
   Skin                                               (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 [3.0]      1 [2.0]      2 [2.5]      1 [3.0]                               
      Hyperkeratosis, Focal                            1 [2.0]                   1 [2.0]                                            
      Inflammation, Focal                                                                     1 [1.0]                               
      Ulcer                                                         1 [3.0]                                                         
      Epidermis, Hyperplasia, Focal                                 1 [2.0]      1 [1.0]                                            
      Subcutaneous Tissue, Edema                                                 1 [3.0]                                            
      Subcutaneous Tissue, Fibrosis, 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   13                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Vertebra, Cyst                                   1 [4.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Compression, Focal                               4 [3.0]      6 [3.2]      1 [3.0]      1 [2.0]                               
      Hemorrhage, Focal                                1 [2.0]      4 [2.5]      3 [2.3]      3 [2.3]                               
      Meninges, Congestion, Focal                                   1 [2.0]                                                         
      Meninges, Hemorrhage, Focal                      1 [2.0]                                                                      
   Spinal Cord                                        (2)          (3)          (2)          (3)                                    
      Hemorrhage, Focal                                             1 [1.0]                   1 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion                                       4 [2.8]      1 [2.0]                   2 [3.0]                               
      Hemorrhage, Focal                                4 [2.3]      1 [3.0]      3 [2.3]                                            
      Infiltration Cellular, Mixed Cell                3 [1.7]                   1 [2.0]      2 [2.0]                               
      Inflammation, Chronic, Focal                     3 [1.3]      3 [2.0]      4 [1.3]      2 [1.0]                               
      Inflammation, Focal                                                                     1 [1.0]                               
      Alveolar Epithelium, Hyperplasia, Focal          2 [2.0]      4 [1.8]      3 [1.7]                                            
      Alveolus, Proteinosis                                                      1 [3.0]                                            
   Nose                                               (49)         (50)         (50)         (50)                                   
      Foreign Body                                     1 [2.0]                   1 [1.0]      1 [2.0]                               
      Hemorrhage                                       1 [3.0]                                                                      
      Inflammation, Suppurative                        2 [2.5]      1 [1.0]      4 [1.8]      2 [2.0]                               
      Nasolacrimal Duct, Inflammation                                                         4 [2.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (48)         (47)         (48)         (45)                                   
      Cataract                                         2 [3.0]      1 [3.0]                   2 [2.0]                               
      Anterior Chamber, Exudate                                     1 [3.0]                   2 [2.5]                               
      Retina, Degeneration                             2 [3.0]                                                                      
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia, Focal, Histiocytic                  1 [3.0]                                                                      
      Hyperplasia, Focal, Lymphoid                                               1 [2.0]                                            
      Inflammation                                                               2 [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   14                                                              
                                                                                                                                   
NTP Experiment-Test: 92013-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 12/06/04    
Route: DOSED FEED                                             4-METHYLIMIDAZOLE                                   Time: 09:00:53    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                        0 PPM        625 PPM      1250 PPM     2500 PPM                               
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
SPECIAL SENSES SYSTEM - CONT                                                                                                        
      Inflammation, Chronic                                                                   1 [3.0]                               
      Epithelium, Hyperplasia, Focal                   1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (48)         (49)         (48)         (50)                                   
      Congestion                                       1 [3.0]                                                                      
      Cyst                                             2 [2.0]      1 [3.0]                                                         
      Infarct                                                       2 [2.5]      1 [3.0]      4 [2.3]                               
      Nephropathy                                     47 [1.6]     43 [1.6]     47 [1.4]     46 [1.7]                               
      Pelvis, Dilatation                                                         1 [2.0]      1 [3.0]                               
      Renal Tubule, Accumulation, Hyaline Droplet      1 [2.0]      3 [2.0]      2 [3.0]      2 [2.0]                               
      Renal Tubule, Hyperplasia, Focal                              1 [1.0]                                                         
      Renal Tubule, Pigmentation                       1 [2.0]      1 [3.0]      2 [3.0]                                            
   Urethra                                                                                   (1)                                    
      Muscularis, Inflammation, Chronic                                                       1 [3.0]                               
   Urinary Bladder                                    (49)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 [3.0]      1 [3.0]                   1 [4.0]                               
      Inflammation                                     1 [1.0]                                1 [3.0]                               
      Ulcer                                            1 [3.0]                                                                      
      Muscularis, Hyperplasia                                                    1 [3.0]                                            
      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   15                                                              
                                                                                                                                   
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