National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/3531

TDMS Study 05120-04 Pathology Tables



                                     INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)
                                                           BENZYL ACETATE


NTP Experiment-Test: 05120-04                                                                                     Report: PEIRPT03
Study Type: CHRONIC                                                                                               Date: 09/16/94
Route: DOSED FEED                                                                                                 Time: 03:33:00




       Facility:  Southern Research Institute

       Chemical CAS #:  140-11-4

       Lock Date:  None

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All
































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

                                                             Page   1

NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          60           60           60           60                                     
  Scheduled Sacrifice                                 10           10           10           10                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                12           16            7            3                                     
    Natural Death                                      9            6            6            3                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                29           28           37           44                                     
  Animals Examined Microscopically                    60           60           60           60                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (60)         (58)         (58)         (60)                                   
      Dilatation                                       2 (3%)       1 (2%)                                                          
      Inflammation, Subacute                                                     1 (2%)                                             
   Intestine Large, Cecum                             (59)         (60)         (60)         (58)                                   
      Edema                                                         1 (2%)                                                          
   Intestine Small, Duodenum                          (59)         (58)         (59)         (59)                                   
      Dilatation                                       1 (2%)                                                                       
   Intestine Small, Ileum                             (58)         (58)         (59)         (59)                                   
      Hyperplasia, Lymphoid                                                                   1 (2%)                                
   Intestine Small, Jejunum                           (58)         (60)         (59)         (59)                                   
      Dilatation                                       1 (2%)                                                                       
      Hyperplasia, Lymphoid                                         1 (2%)                    2 (3%)                                
   Liver                                              (60)         (60)         (60)         (60)                                   
      Angiectasis                                                   2 (3%)       2 (3%)                                             
      Basophilic Focus                                 4 (7%)       2 (3%)                    5 (8%)                                
      Clear Cell Focus                                 2 (3%)       2 (3%)       2 (3%)                                             
      Cyst                                             1 (2%)       1 (2%)                                                          
      Fibrosis                                                                   1 (2%)                                             
      Hematopoietic Cell Proliferation                13 (22%)      7 (12%)     10 (17%)      1 (2%)                                
      Hemorrhage                                                                 1 (2%)                                             
      Hyperplasia, Focal                               2 (3%)       2 (3%)       2 (3%)                                             
      Hyperplasia, Lymphoid                            3 (5%)       5 (8%)       5 (8%)       2 (3%)                                
      Inflammation, Subacute                          12 (20%)      4 (7%)       7 (12%)     13 (22%)                               
      Metaplasia, Osseous                                                        1 (2%)                                             
      Mineralization                                   1 (2%)                    1 (2%)                                             
      Mixed Cell Focus                                 2 (3%)       2 (3%)                    1 (2%)                                
      Nuclear Alteration                                                         3 (5%)                                             
      Bile Duct, Hyperplasia                           2 (3%)                                                                       
      Centrilobular, Necrosis                                       1 (2%)                                                          
      Hepatocyte, Cytomegaly                           1 (2%)                                                                       
      Hepatocyte, Karyomegaly                          1 (2%)                                                                       
      Hepatocyte, Vacuolization Cytoplasmic            3 (5%)       1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Kupffer Cell, Hyperplasia                        7 (12%)      6 (10%)     11 (18%)      5 (8%)                                
      Kupffer Cell, Pigmentation                       2 (3%)                    5 (8%)       2 (3%)                                
      Lobules, Necrosis                                7 (12%)      8 (13%)      4 (7%)       6 (10%)                               
   Mesentery                                          (9)          (7)          (7)          (3)                                    
      Inflammation, Suppurative                        3 (33%)      3 (43%)      4 (57%)      1 (33%)                               
      Capillary, Fat, Congestion                                                              1 (33%)                               
      Fat, Necrosis                                    2 (22%)      2 (29%)      1 (14%)                                            
   Pancreas                                           (60)         (60)         (60)         (59)                                   
      Atrophy                                          4 (7%)                    5 (8%)       2 (3%)                                
      Cyst                                                          1 (2%)       4 (7%)       1 (2%)                                
      Focal Cellular Change                                                      2 (3%)                                             
      Hyperplasia, Lymphoid                            4 (7%)       2 (3%)       8 (13%)      4 (7%)                                
      Necrosis                                         2 (3%)                                                                       
      Acinar Cell, Cytoplasmic Alteration              8 (13%)      2 (3%)       3 (5%)                                             
   Salivary Glands                                    (60)         (60)         (60)         (60)                                   
      Atrophy                                                       1 (2%)                                                          
      Hyperplasia, Lymphoid                           11 (18%)     13 (22%)     13 (22%)     15 (25%)                               
   Stomach, Forestomach                               (59)         (60)         (60)         (60)                                   
      Diverticulum                                                  2 (3%)       2 (3%)       2 (3%)                                
      Edema                                            1 (2%)                                 1 (2%)                                
      Inflammation, Subacute                           4 (7%)                    7 (12%)      2 (3%)                                
      Ulcer                                            2 (3%)                                                                       
      Mucosa, Hyperplasia                              8 (14%)      6 (10%)      9 (15%)      3 (5%)                                
   Stomach, Glandular                                 (60)         (60)         (60)         (60)                                   
      Cyst                                             6 (10%)      3 (5%)       3 (5%)       2 (3%)                                
      Edema                                            1 (2%)                                 1 (2%)                                
      Erosion                                          4 (7%)       1 (2%)       1 (2%)                                             
      Inflammation, Chronic                            2 (3%)                                                                       
      Inflammation, Subacute                           1 (2%)       1 (2%)       1 (2%)                                             
      Ulcer                                                         1 (2%)                                                          
      Mucosa, Dysplasia                                             1 (2%)                                                          
   Tongue                                             (60)         (60)         (60)         (60)                                   
      Inflammation, Chronic                            1 (2%)       3 (5%)       2 (3%)                                             
      Mineralization                                                                          1 (2%)                                
   Tooth                                                           (1)                                                              
      Dysplasia                                                     1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (2)                       (2)          (5)                                    
      Inflammation, Chronic Active                     2 (100%)                  2 (100%)     5 (100%)                              
   Heart                                              (60)         (60)         (60)         (60)                                   
      Cardiomyopathy                                   1 (2%)                                 1 (2%)                                
      Thrombosis                                       1 (2%)                                                                       
      Myocardium, Inflammation, Chronic                2 (3%)       2 (3%)                                                          
      Myocardium, Mineralization                       1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (60)         (60)         (60)         (60)                                   
      Accessory Adrenal Cortical Nodule               17 (28%)      6 (10%)     14 (23%)     14 (23%)                               
      Angiectasis                                                                1 (2%)       1 (2%)                                
      Cyst                                                                       2 (3%)       2 (3%)                                
      Developmental Malformation                                                              1 (2%)                                
      Hematopoietic Cell Proliferation                 3 (5%)       2 (3%)       4 (7%)                                             
      Hyperplasia, Diffuse                                          1 (2%)       1 (2%)                                             
      Hyperplasia, Focal                               1 (2%)                    1 (2%)       1 (2%)                                
      Hypertrophy, Focal                                            1 (2%)                    2 (3%)                                
      Inflammation, Subacute                           1 (2%)                                                                       
      Vacuolization Cytoplasmic, Focal                              1 (2%)                                                          
      Capsule, Hyperplasia                             1 (2%)       1 (2%)       5 (8%)       5 (8%)                                
      X-Zone, Degeneration, Fatty                                   1 (2%)                    1 (2%)                                
   Adrenal Gland, Medulla                             (60)         (60)         (60)         (60)                                   
      Hyperplasia                                      2 (3%)       4 (7%)       5 (8%)       3 (5%)                                
   Islets, Pancreatic                                 (60)         (60)         (60)         (59)                                   
      Hyperplasia                                      5 (8%)       1 (2%)                                                          
   Parathyroid Gland                                  (56)         (60)         (57)         (55)                                   
      Cyst                                             2 (4%)                    1 (2%)       1 (2%)                                
      Ectopic Thymus                                                1 (2%)                    2 (4%)                                
      Hyperplasia                                      1 (2%)                    1 (2%)                                             
   Pituitary Gland                                    (57)         (56)         (60)         (59)                                   
      Pars Distalis, Angiectasis                       5 (9%)       4 (7%)       6 (10%)                                            
      Pars Distalis, Cyst                              1 (2%)                    1 (2%)       1 (2%)                                
      Pars Distalis, Hyperplasia                      18 (32%)     14 (25%)     15 (25%)     14 (24%)                               
      Pars Intermedia, Hyperplasia                     1 (2%)                                                                       
   Thyroid Gland                                      (60)         (60)         (60)         (60)                                   
      Degeneration, Cystic                            10 (17%)      9 (15%)     14 (23%)     13 (22%)                               
      Ectopic Thymus                                   2 (3%)                                 1 (2%)                                
      Inflammation, Subacute                           1 (2%)                                                                       
      Follicle, Cyst                                   5 (8%)       3 (5%)       2 (3%)       5 (8%)                                
      Follicular Cell, Hyperplasia                    11 (18%)     10 (17%)     12 (20%)     17 (28%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (1)          (1)                       (1)                                    
      Infiltration Cellular, Lymphocyte                1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (1)          (1)          (1)                                                 
      Ectasia                                          1 (100%)                                                                     
      Pigmentation                                     1 (100%)                  1 (100%)                                           
   Ovary                                              (59)         (58)         (59)         (59)                                   
      Angiectasis                                      8 (14%)      8 (14%)      9 (15%)      5 (8%)                                
      Cyst                                            11 (19%)     14 (24%)     16 (27%)     17 (29%)                               
      Hemorrhage                                       1 (2%)       2 (3%)       1 (2%)       1 (2%)                                
      Inflammation, Suppurative                       13 (22%)      7 (12%)     10 (17%)      4 (7%)                                
      Pigmentation                                     1 (2%)                                 2 (3%)                                
      Thrombosis                                                    1 (2%)                                                          
      Interstitial Cell, Hyperplasia                   4 (7%)                    1 (2%)       1 (2%)                                
   Uterus                                             (60)         (59)         (60)         (60)                                   
      Angiectasis                                      2 (3%)       2 (3%)       3 (5%)       3 (5%)                                
      Granuloma                                                                  1 (2%)       1 (2%)                                
      Hemorrhage                                                                 1 (2%)                                             
      Hydrometra                                       1 (2%)       3 (5%)       4 (7%)       2 (3%)                                
      Hyperplasia, Cystic                             56 (93%)     55 (93%)     58 (97%)     58 (97%)                               
      Inflammation, Suppurative                       14 (23%)      6 (10%)     10 (17%)      6 (10%)                               
      Necrosis                                                                   1 (2%)       2 (3%)                                
      Endometrium, Pigmentation                        1 (2%)                    1 (2%)                                             
      Epithelium, Metaplasia, Squamous                 7 (12%)      8 (14%)     15 (25%)      7 (12%)                               
      Myometrium, Hyperplasia                                       1 (2%)       1 (2%)       1 (2%)                                
   Vagina                                             (1)                                                                           
      Granuloma                                        1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (60)         (60)         (60)         (60)                                   
      Hypercellularity                                19 (32%)     11 (18%)     20 (33%)      8 (13%)                               
      Myelofibrosis                                   16 (27%)     12 (20%)     14 (23%)     15 (25%)                               
      Necrosis                                                      1 (2%)                                                          
      Pigmentation, Hemosiderin                        3 (5%)       2 (3%)       7 (12%)      4 (7%)                                
   Lymph Node                                         (60)         (60)         (60)         (59)                                   
      Iliac, Angiectasis                               1 (2%)                                                                       
      Iliac, Hematopoietic Cell Proliferation          2 (3%)                                                                       
      Iliac, Hyperplasia, Lymphoid                                  2 (3%)                                                          
      Iliac, Hyperplasia, Plasma Cell                  2 (3%)       3 (5%)                    1 (2%)                                
      Lumbar, Hyperplasia, Lymphoid                                              1 (2%)                                             
      Lumbar, Hyperplasia, Plasma Cell                 2 (3%)                                                                       
      Mediastinal, Hyperplasia, Plasma Cell            5 (8%)       4 (7%)       2 (3%)                                             
      Mediastinal, Inflammation, Suppurative           1 (2%)       2 (3%)                                                          
      Renal, Ectasia                                   1 (2%)                                                                       
      Renal, Hematopoietic Cell Proliferation          2 (3%)                    1 (2%)                                             
      Renal, Hemorrhage                                                          1 (2%)                                             
      Renal, Hyperplasia, Lymphoid                     3 (5%)       1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Renal, Hyperplasia, Plasma Cell                  5 (8%)       5 (8%)       3 (5%)       1 (2%)                                
   Lymph Node, Mandibular                             (60)         (58)         (60)         (59)                                   
      Hematopoietic Cell Proliferation                 2 (3%)       1 (2%)       2 (3%)                                             
      Hyperplasia, Lymphoid                            5 (8%)       5 (9%)       5 (8%)                                             
      Hyperplasia, Plasma Cell                         6 (10%)      4 (7%)       1 (2%)       1 (2%)                                
      Pigmentation                                     1 (2%)       2 (3%)       1 (2%)                                             
   Lymph Node, Mesenteric                             (60)         (56)         (59)         (58)                                   
      Angiectasis                                      2 (3%)                    1 (2%)                                             
      Ectasia                                                                                 2 (3%)                                
      Hematopoietic Cell Proliferation                11 (18%)      5 (9%)       4 (7%)       2 (3%)                                
      Hemorrhage                                       7 (12%)      3 (5%)       5 (8%)       6 (10%)                               
      Hyperplasia, Lymphoid                            3 (5%)       3 (5%)       3 (5%)       3 (5%)                                
      Hyperplasia, Plasma Cell                         2 (3%)                    1 (2%)                                             
      Necrosis                                                      1 (2%)                                                          
   Spleen                                             (60)         (60)         (60)         (59)                                   
      Hematopoietic Cell Proliferation                27 (45%)     24 (40%)     27 (45%)     15 (25%)                               
      Hyperplasia, Reticulum Cell                      2 (3%)                                                                       
      Pigmentation, Hemosiderin                        8 (13%)      7 (12%)      6 (10%)      2 (3%)                                
      Lymphoid Follicle, Atrophy                       1 (2%)       1 (2%)       1 (2%)                                             
      Lymphoid Follicle, Hyperplasia                   4 (7%)       6 (10%)      6 (10%)      6 (10%)                               
      Red Pulp, Hyperplasia                            3 (5%)       1 (2%)       1 (2%)       1 (2%)                                
   Thymus                                             (55)         (56)         (56)         (57)                                   
      Angiectasis                                      4 (7%)       2 (4%)                    1 (2%)                                
      Cyst                                             9 (16%)      3 (5%)      11 (20%)     13 (23%)                               
      Depletion Cellular                               8 (15%)      9 (16%)      6 (11%)      2 (4%)                                
      Ectopic Parathyroid Gland                        2 (4%)                                                                       
      Hyperplasia, Lymphoid                            3 (5%)       2 (4%)                    2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (60)         (59)         (60)         (60)                                   
      Hyperplasia, Cystic                              5 (8%)       4 (7%)                    2 (3%)                                
      Hyperplasia, Lobular                             1 (2%)                                 1 (2%)                                
   Skin                                               (60)         (60)         (59)         (60)                                   
      Acanthosis                                       2 (3%)       1 (2%)       4 (7%)       3 (5%)                                
      Cyst Epithelial Inclusion                                                               1 (2%)                                
      Inflammation, Chronic                            3 (5%)       1 (2%)       3 (5%)       2 (3%)                                
      Ulcer                                                                      1 (2%)       1 (2%)                                
      Subcutaneous Tissue, Edema                       2 (3%)       2 (3%)       2 (3%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (60)         (60)         (60)         (60)                                   
      Foreign Body                                                               1 (2%)                                             
      Inflammation, Chronic                            7 (12%)      2 (3%)       7 (12%)      1 (2%)                                
      Sarcolemmal Nuclei, Hyperplasia                  1 (2%)       1 (2%)       4 (7%)                                             
      Sarcoplasm, Atrophy                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (60)         (60)         (60)         (60)                                   
      Compression                                      3 (5%)       3 (5%)                    1 (2%)                                
      Cyst                                                          1 (2%)                                                          
      Hydrocephalus                                    1 (2%)                                                                       
      Inflammation, Chronic                            1 (2%)                    1 (2%)       1 (2%)                                
      Vacuolization Cytoplasmic                        1 (2%)                    1 (2%)                                             
      Glial Cell, Proliferation                        1 (2%)                                                                       
      Thalamus, Mineralization                        38 (63%)     53 (88%)     47 (78%)     42 (70%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (60)         (60)         (60)         (60)                                   
      Adenomatosis                                     1 (2%)                                                                       
      Bacterium                                        1 (2%)       1 (2%)       1 (2%)                                             
      Congestion                                       1 (2%)                                                                       
      Edema                                            1 (2%)                                 1 (2%)                                
      Hemorrhage                                       1 (2%)       6 (10%)      4 (7%)       4 (7%)                                
      Hyperplasia, Lymphoid                            9 (15%)      7 (12%)     10 (17%)     14 (23%)                               
      Infiltration Cellular, Histiocyte                7 (12%)      4 (7%)       3 (5%)       1 (2%)                                
      Inflammation, Subacute                                        1 (2%)       3 (5%)                                             
      Inflammation, Suppurative                        2 (3%)                                                                       
      Thrombosis                                       2 (3%)                                                                       
      Alveolar Epithelium, Hyperplasia                 1 (2%)       1 (2%)       1 (2%)                                             
      Artery, Hypertrophy                              1 (2%)       1 (2%)                                                          
      Bronchiole, Foreign Body                         1 (2%)                    3 (5%)       1 (2%)                                
   Nose                                               (60)         (60)         (60)         (60)                                   
      Exudate                                         15 (25%)     26 (43%)     36 (60%)     45 (75%)                               
      Glands, Cyst                                                                            1 (2%)                                
      Glands, Hyperplasia, Cystic                     47 (78%)     54 (90%)     59 (98%)     60 (100%)                              
      Mucosa, Atrophy                                 46 (77%)     57 (95%)     59 (98%)     60 (100%)                              
      Mucosa, Degeneration                            58 (97%)     57 (95%)     60 (100%)    60 (100%)                              
      Mucosa, Pigmentation                                         53 (88%)     58 (97%)     58 (97%)                               
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (60)         (60)         (60)         (60)                                   
      Bacterium                                        1 (2%)       1 (2%)       1 (2%)                                             
      Casts Protein                                   39 (65%)     39 (65%)     38 (63%)     31 (52%)                               
      Cyst                                             2 (3%)       2 (3%)                    2 (3%)                                
      Glomerulosclerosis                               7 (12%)                   5 (8%)       1 (2%)                                
      Hydronephrosis                                                             1 (2%)                                             
      Hyperplasia, Lymphoid                           28 (47%)     27 (45%)     22 (37%)     23 (38%)                               
      Inflammation, Suppurative                        5 (8%)                                                                       
      Metaplasia, Osseous                                           2 (3%)       2 (3%)                                             
      Mineralization                                                2 (3%)       1 (2%)       3 (5%)                                
      Interstitial Tissue, Pigmentation                2 (3%)                                                                       
      Renal Tubule, Atrophy                            2 (3%)       1 (2%)                    1 (2%)                                
      Renal Tubule, Cytoplasmic Alteration                          1 (2%)                                                          
      Renal Tubule, Dilatation                         6 (10%)      1 (2%)       2 (3%)                                             
      Renal Tubule, Necrosis                           1 (2%)       1 (2%)                                                          
      Renal Tubule, Pigmentation                       1 (2%)       2 (3%)                                                          
      Renal Tubule, Regeneration                      22 (37%)      9 (15%)     15 (25%)     14 (23%)                               
      Transitional Epithelium, Hyperplasia             1 (2%)                                                                       
   Urinary Bladder                                    (60)         (59)         (60)         (60)                                   
      Edema                                            1 (2%)       1 (2%)                                                          
      Hyperplasia, Lymphoid                           24 (40%)     15 (25%)     22 (37%)     17 (28%)                               
      Inflammation, Chronic                            1 (2%)                                                                       
      Mucosa, Hyperplasia                              2 (3%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          60           60           60           60                                     
  Scheduled Sacrifice                                 10           10           10           10                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 7            3            6            7                                     
    Natural Death                                      4            4            3            4                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                39           43           41           39                                     
  Animals Examined Microscopically                    60           60           60           60                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (57)         (60)         (58)         (60)                                   
      Cyst                                                                                    1 (2%)                                
      Inflammation, Subacute                                        1 (2%)                    1 (2%)                                
      Mucosa, Hyperplasia                                           1 (2%)                    1 (2%)                                
   Intestine Large, Cecum                             (59)         (58)         (60)         (58)                                   
      Edema                                                                                   1 (2%)                                
   Intestine Small, Ileum                             (58)         (59)         (60)         (58)                                   
      Hyperplasia, Lymphoid                                         1 (2%)                    1 (2%)                                
      Inflammation, Chronic                                                      1 (2%)                                             
   Intestine Small, Jejunum                           (60)         (59)         (60)         (59)                                   
      Hyperplasia, Lymphoid                                         2 (3%)       1 (2%)       1 (2%)                                
   Liver                                              (60)         (60)         (60)         (60)                                   
      Basophilic Focus                                 2 (3%)       2 (3%)                    2 (3%)                                
      Clear Cell Focus                                 7 (12%)      4 (7%)       5 (8%)       2 (3%)                                
      Hematopoietic Cell Proliferation                              2 (3%)       1 (2%)       1 (2%)                                
      Hyperplasia, Focal                               2 (3%)       3 (5%)       1 (2%)                                             
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                                                          
      Inflammation, Subacute                           1 (2%)       3 (5%)       2 (3%)       3 (5%)                                
      Mixed Cell Focus                                 3 (5%)       2 (3%)       2 (3%)       2 (3%)                                
      Nuclear Alteration                               1 (2%)       1 (2%)                                                          
      Thrombosis                                                    1 (2%)                                                          
      Bile Duct, Hyperplasia                                                                  1 (2%)                                
      Centrilobular, Necrosis                          1 (2%)       2 (3%)       1 (2%)       1 (2%)                                
      Hepatocyte, Cytomegaly                           2 (3%)                    1 (2%)                                             
      Hepatocyte, Vacuolization Cytoplasmic            4 (7%)       1 (2%)       2 (3%)       2 (3%)                                
      Kupffer Cell, Hyperplasia                        3 (5%)       2 (3%)       2 (3%)       4 (7%)                                
      Kupffer Cell, Pigmentation                                                 1 (2%)       2 (3%)                                
      Lobules, Necrosis                                4 (7%)       1 (2%)       2 (3%)       4 (7%)                                
   Mesentery                                          (3)          (3)          (2)          (1)                                    
      Inflammation, Suppurative                                     1 (33%)                                                         
      Fat, Hemorrhage                                               1 (33%)                                                         
      Fat, Necrosis                                    2 (67%)      1 (33%)      2 (100%)                                           
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Pancreas                                           (60)         (60)         (60)         (60)                                   
      Atrophy                                          2 (3%)       2 (3%)       2 (3%)                                             
      Cyst                                                          1 (2%)                                                          
      Focal Cellular Change                            3 (5%)       2 (3%)       1 (2%)       1 (2%)                                
      Hyperplasia, Lymphoid                                                      1 (2%)       1 (2%)                                
      Acinar Cell, Cytoplasmic Alteration              3 (5%)       2 (3%)                    5 (8%)                                
      Acinar Cell, Hyperplasia, Focal                                                         1 (2%)                                
   Pharynx                                            (1)                                                                           
      Ulcer                                            1 (100%)                                                                     
   Salivary Glands                                    (60)         (60)         (60)         (60)                                   
      Hyperplasia, Lymphoid                            8 (13%)      4 (7%)       5 (8%)       7 (12%)                               
   Stomach, Forestomach                               (60)         (60)         (60)         (60)                                   
      Diverticulum                                                  3 (5%)                    3 (5%)                                
      Erosion                                                                                 1 (2%)                                
      Inflammation, Subacute                           3 (5%)       3 (5%)       3 (5%)       1 (2%)                                
      Mucosa, Hyperplasia                              5 (8%)       4 (7%)       5 (8%)       3 (5%)                                
   Stomach, Glandular                                 (60)         (60)         (60)         (60)                                   
      Cyst                                             5 (8%)       6 (10%)      2 (3%)       6 (10%)                               
      Erosion                                          3 (5%)                                                                       
      Ulcer                                                                                   1 (2%)                                
   Tongue                                             (60)         (60)         (60)         (60)                                   
      Inflammation, Chronic                                         1 (2%)                                                          
      Epithelium, Degeneration, Ballooning                                                    1 (2%)                                
   Tooth                                              (3)          (4)          (1)          (2)                                    
      Dysplasia                                        3 (100%)     3 (75%)      1 (100%)     2 (100%)                              
      Inflammation, Chronic                                         1 (25%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (1)          (1)          (2)          (1)                                    
      Inflammation, Chronic Active                     1 (100%)     1 (100%)     2 (100%)     1 (100%)                              
   Heart                                              (60)         (60)         (60)         (60)                                   
      Cardiomyopathy                                                                          2 (3%)                                
      Myocardium, Hemorrhage                                                                  1 (2%)                                
      Myocardium, Inflammation, Chronic                                                       2 (3%)                                
      Myocardium, Mineralization                                    1 (2%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (60)         (60)         (60)         (60)                                   
      Accessory Adrenal Cortical Nodule                9 (15%)     10 (17%)      8 (13%)      8 (13%)                               
      Angiectasis                                      1 (2%)       1 (2%)                                                          
      Cyst                                             1 (2%)                                                                       
      Hyperplasia, Diffuse                                                       1 (2%)                                             
      Hyperplasia, Focal                               7 (12%)     13 (22%)      8 (13%)      7 (12%)                               
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hypertrophy, Focal                              29 (48%)     22 (37%)     23 (38%)     26 (43%)                               
      Vacuolization Cytoplasmic, Focal                 5 (8%)       4 (7%)       2 (3%)       5 (8%)                                
      Capsule, Hyperplasia                            11 (18%)      8 (13%)      9 (15%)      7 (12%)                               
   Adrenal Gland, Medulla                             (60)         (60)         (60)         (60)                                   
      Hyperplasia                                      2 (3%)                    1 (2%)       1 (2%)                                
   Islets, Pancreatic                                 (60)         (60)         (59)         (60)                                   
      Cyst                                             1 (2%)                                                                       
      Hyperplasia                                     11 (18%)     13 (22%)     11 (19%)      4 (7%)                                
   Parathyroid Gland                                  (52)         (58)         (55)         (59)                                   
      Cyst                                             1 (2%)       2 (3%)       2 (4%)                                             
      Ectopic Thymus                                                             1 (2%)                                             
   Pituitary Gland                                    (58)         (59)         (58)         (57)                                   
      Pars Distalis, Cyst                              4 (7%)       1 (2%)       3 (5%)                                             
      Pars Distalis, Hyperplasia                       2 (3%)       1 (2%)       2 (3%)                                             
      Pars Intermedia, Hyperplasia                                                            1 (2%)                                
   Thyroid Gland                                      (60)         (60)         (60)         (60)                                   
      Degeneration, Cystic                             5 (8%)       4 (7%)       8 (13%)      8 (13%)                               
      Follicle, Cyst                                   6 (10%)      2 (3%)       3 (5%)       5 (8%)                                
      Follicular Cell, Hyperplasia                     6 (10%)      8 (13%)      7 (12%)      2 (3%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                               (1)                                                              
      Dilatation                                                    1 (100%)                                                        
   Epididymis                                         (60)         (60)         (60)         (60)                                   
      Atypia Cellular                                  1 (2%)       1 (2%)       2 (3%)       2 (3%)                                
      Hypospermia                                                                1 (2%)                                             
      Inflammation, Chronic                            1 (2%)       1 (2%)       1 (2%)                                             
      Spermatocele                                                               1 (2%)                                             
   Preputial Gland                                    (38)         (42)         (35)         (25)                                   
      Atrophy                                          1 (3%)                                                                       
      Ectasia                                         33 (87%)     40 (95%)     32 (91%)     24 (96%)                               
      Inflammation, Chronic                           18 (47%)     25 (60%)     18 (51%)     11 (44%)                               
      Inflammation, Suppurative                        3 (8%)       4 (10%)      1 (3%)                                             
   Prostate                                           (60)         (60)         (60)         (60)                                   
      Fibrosis                                         1 (2%)                                                                       
      Hemorrhage                                       1 (2%)       1 (2%)                    1 (2%)                                
      Inflammation, Chronic                            1 (2%)       4 (7%)                    1 (2%)                                
      Inflammation, Suppurative                        1 (2%)                                                                       
      Epithelium, Hyperplasia                          1 (2%)                                                                       
   Seminal Vesicle                                    (60)         (60)         (60)         (60)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Depletion Cellular                                            1 (2%)                                                          
      Dilatation                                       1 (2%)       1 (2%)                                                          
      Fibrosis                                                                   1 (2%)                                             
      Hemorrhage                                                                 1 (2%)                                             
      Inflammation, Chronic                                         1 (2%)                                                          
   Testes                                             (60)         (60)         (60)         (60)                                   
      Angiectasis                                                                1 (2%)                                             
      Granuloma Sperm                                                                         2 (3%)                                
      Mineralization                                                                          1 (2%)                                
      Seminiferous Tubule, Atrophy                     1 (2%)                    3 (5%)       6 (10%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (60)         (60)         (60)         (60)                                   
      Hypercellularity                                 8 (13%)      6 (10%)      3 (5%)       4 (7%)                                
      Necrosis                                         1 (2%)                                                                       
      Pigmentation, Hemosiderin                        2 (3%)       1 (2%)       2 (3%)                                             
   Lymph Node                                         (60)         (60)         (60)         (60)                                   
      Inguinal, Hyperplasia, Lymphoid                  2 (3%)       1 (2%)                                                          
      Mediastinal, Hyperplasia, Lymphoid                                                      1 (2%)                                
      Mediastinal, Hyperplasia, Plasma Cell                         2 (3%)                                                          
   Lymph Node, Mandibular                             (58)         (56)         (60)         (59)                                   
      Depletion Cellular                               1 (2%)                                                                       
      Hyperplasia, Lymphoid                            1 (2%)       3 (5%)       4 (7%)                                             
      Hyperplasia, Plasma Cell                         3 (5%)       1 (2%)                    1 (2%)                                
      Pigmentation                                                               2 (3%)                                             
   Lymph Node, Mesenteric                             (58)         (59)         (60)         (60)                                   
      Angiectasis                                                                             1 (2%)                                
      Depletion Cellular                               1 (2%)                                                                       
      Ectasia                                                       1 (2%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                 3 (5%)       5 (8%)       8 (13%)      1 (2%)                                
      Hemorrhage                                      18 (31%)     24 (41%)     19 (32%)     23 (38%)                               
      Hyperplasia, Lymphoid                            4 (7%)       5 (8%)       1 (2%)       4 (7%)                                
      Hyperplasia, Plasma Cell                         1 (2%)       1 (2%)       1 (2%)                                             
      Necrosis                                                                   1 (2%)                                             
      Pigmentation                                                  1 (2%)                    1 (2%)                                
   Spleen                                             (60)         (60)         (60)         (60)                                   
      Hematopoietic Cell Proliferation                13 (22%)     14 (23%)      9 (15%)      8 (13%)                               
      Hyperplasia, Reticulum Cell                      1 (2%)                                                                       
      Necrosis                                         1 (2%)                                                                       
      Lymphoid Follicle, Atrophy                       1 (2%)       1 (2%)       1 (2%)       3 (5%)                                
      Lymphoid Follicle, Hyperplasia                   1 (2%)       1 (2%)       1 (2%)       3 (5%)                                
      Red Pulp, Atrophy                                1 (2%)                    1 (2%)       1 (2%)                                
      Red Pulp, Hyperplasia                                                      1 (2%)                                             
   Thymus                                             (52)         (55)         (57)         (54)                                   
      Cyst                                            12 (23%)     12 (22%)     15 (26%)     10 (19%)                               
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Depletion Cellular                               4 (8%)       4 (7%)       4 (7%)       5 (9%)                                
      Ectopic Parathyroid Gland                                                               1 (2%)                                
      Hyperplasia, Lymphoid                                                                   2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (60)         (60)         (60)         (60)                                   
      Acanthosis                                       2 (3%)       1 (2%)                    2 (3%)                                
      Granuloma                                                     1 (2%)                                                          
      Hemorrhage                                                    1 (2%)                                                          
      Inflammation, Chronic                                                      2 (3%)       1 (2%)                                
      Subcutaneous Tissue, Edema                       1 (2%)       1 (2%)       1 (2%)       2 (3%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (60)         (60)         (60)         (60)                                   
      Dysplasia                                                                               1 (2%)                                
      Hyperostosis                                                               2 (3%)                                             
   Skeletal Muscle                                    (60)         (60)         (60)         (60)                                   
      Inflammation, Chronic                                         1 (2%)       3 (5%)       2 (3%)                                
      Sarcolemmal Nuclei, Hyperplasia                  1 (2%)       2 (3%)       1 (2%)       2 (3%)                                
      Sarcoplasm, Atrophy                              1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (60)         (60)         (60)         (60)                                   
      Compression                                                                1 (2%)                                             
      Ectopic Tissue                                                1 (2%)                                                          
      Hydrocephalus                                                              1 (2%)                                             
      Vacuolization Cytoplasmic                                                  1 (2%)       1 (2%)                                
      Glial Cell, Proliferation                                                  1 (2%)                                             
      Thalamus, Mineralization                        46 (77%)     48 (80%)     54 (90%)     47 (78%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (60)         (60)         (60)         (60)                                   
      Angiectasis                                                   1 (2%)                                                          
      Congestion                                                                              1 (2%)                                
      Hemorrhage                                                    2 (3%)       2 (3%)       5 (8%)                                
      Hyperplasia, Lymphoid                            5 (8%)       2 (3%)                    2 (3%)                                
      Infiltration Cellular, Histiocyte                7 (12%)      8 (13%)      8 (13%)      4 (7%)                                
      Inflammation, Suppurative                                     1 (2%)                                                          
      Thrombosis                                       1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
NTP Experiment-Test: 05120-04         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           BENZYL ACETATE                                      Date: 09/16/94  
Route: DOSED FEED                                                                                                 Time: 03:33:00  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          0%           .033%        .1%          .3%                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Alveolar Epithelium, Hyperplasia                 1 (2%)       3 (5%)       6 (10%)      1 (2%)                                
   Nose                                               (60)         (60)         (60)         (60)                                   
      Cyst                                             1 (2%)                                                                       
      Developmental Malformation                                                              1 (2%)                                
      Exudate                                          8 (13%)     18 (30%)     39 (65%)     31 (52%)                               
      Glands, Hyperplasia, Cystic                     24 (40%)     46 (77%)     48 (80%)     60 (100%)                              
      Mucosa, Atrophy                                 30 (50%)     57 (95%)     60 (100%)    60 (100%)                              
      Mucosa, Degeneration                            36 (60%)     55 (92%)     60 (100%)    60 (100%)                              
      Mucosa, Metaplasia, Squamous                     1 (2%)                                                                       
      Mucosa, Pigmentation                                         52 (87%)     60 (100%)    60 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                                          (3)          (1)                                    
      Inflammation, Chronic                                                      3 (100%)     1 (100%)                              
      Cornea, Hyperplasia                                                        3 (100%)     1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (60)         (60)         (60)         (60)                                   
      Casts Protein                                   10 (17%)     16 (27%)     13 (22%)      7 (12%)                               
      Cyst                                            21 (35%)     16 (27%)     16 (27%)     17 (28%)                               
      Glomerulosclerosis                               1 (2%)       4 (7%)       1 (2%)       2 (3%)                                
      Hyperplasia, Lymphoid                           18 (30%)     17 (28%)     15 (25%)     12 (20%)                               
      Inflammation, Suppurative                        2 (3%)                                                                       
      Mineralization                                  29 (48%)     48 (80%)     42 (70%)     38 (63%)                               
      Renal Tubule, Atrophy                            6 (10%)      3 (5%)       5 (8%)       2 (3%)                                
      Renal Tubule, Dilatation                         2 (3%)       1 (2%)       1 (2%)       2 (3%)                                
      Renal Tubule, Hyperplasia                        2 (3%)       1 (2%)                    1 (2%)                                
      Renal Tubule, Pigmentation                                                              1 (2%)                                
      Renal Tubule, Regeneration                      57 (95%)     51 (85%)     47 (78%)     51 (85%)                               
      Transitional Epithelium, Hyperplasia             1 (2%)       1 (2%)                                                          
   Urinary Bladder                                    (60)         (60)         (60)         (60)                                   
      Dilatation                                                    1 (2%)                    1 (2%)                                
      Hyperplasia, Lymphoid                            2 (3%)       2 (3%)       2 (3%)                                             
      Inflammation, Chronic                            1 (2%)                                                                       
      Inflammation, Suppurative                        2 (3%)                                                                       
      Mucosa, Hyperplasia                              1 (2%)                                                                       
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   14                                                              
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------                                           
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.