National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2532

TDMS Study 05156-06 Pathology Tables

NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  10026-24-1

       Lock Date:  07/12/94

       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: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      5            3            5            6                                     
    Moribund Sacrifice                                11           10           13           16                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                34           37           32           28                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (49)         (49)         (48)         (47)                                   
      Inflammation                                                               1 (2%)                                             
   Intestine Small, Ileum                             (48)         (48)         (47)         (45)                                   
      Peyer's Patch, Hyperplasia, Lymphoid                                       1 (2%)                                             
   Liver                                              (50)         (50)         (50)         (49)                                   
      Basophilic Focus                                              1 (2%)                                                          
      Clear Cell Focus                                 2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
      Clear Cell Focus, Multiple                                                              1 (2%)                                
      Cyst                                                                       1 (2%)       1 (2%)                                
      Eosinophilic Focus                               9 (18%)      7 (14%)      8 (16%)      9 (18%)                               
      Eosinophilic Focus, Multiple                                                            1 (2%)                                
      Hematopoietic Cell Proliferation                              1 (2%)                    1 (2%)                                
      Hemorrhage                                                    1 (2%)                                                          
      Infiltration Cellular, Lymphocyte                3 (6%)       2 (4%)       1 (2%)       1 (2%)                                
      Infiltration Cellular, Mixed Cell                             1 (2%)                                                          
      Inflammation, Chronic                            6 (12%)      1 (2%)       1 (2%)       2 (4%)                                
      Karyomegaly                                      4 (8%)       2 (4%)                    1 (2%)                                
      Mineralization                                                             1 (2%)                                             
      Necrosis                                         1 (2%)                                                                       
      Necrosis, Focal                                  3 (6%)       1 (2%)       2 (4%)       2 (4%)                                
      Regeneration                                     1 (2%)                                                                       
      Thrombosis                                                                              1 (2%)                                
      Vacuolization Cytoplasmic                                     1 (2%)                                                          
      Vacuolization Cytoplasmic, Diffuse                                         1 (2%)       1 (2%)                                
      Oval Cell, Hyperplasia                           2 (4%)       1 (2%)                                                          
      Serosa, Fibrosis                                                                        1 (2%)                                
   Mesentery                                          (10)         (12)         (8)          (7)                                    
      Angiectasis                                      1 (10%)                                                                      
      Hemorrhage                                                                              1 (14%)                               
      Infiltration Cellular, Lymphocyte                             1 (8%)                                                          
      Inflammation, Chronic                                         1 (8%)                                                          
      Fat, Necrosis                                    7 (70%)      8 (67%)      7 (88%)      5 (71%)                               
   Pancreas                                           (50)         (50)         (49)         (49)                                   
      Infiltration Cellular, Lymphocyte                                          1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Inflammation, Chronic                            1 (2%)       1 (2%)                                                          
      Acinus, Atrophy                                  1 (2%)       2 (4%)                    3 (6%)                                
      Duct, Cyst                                       1 (2%)       2 (4%)       1 (2%)                                             
   Stomach, Forestomach                               (50)         (50)         (49)         (50)                                   
      Cyst                                                          1 (2%)                                                          
      Hyperplasia, Squamous                            1 (2%)       3 (6%)       1 (2%)       3 (6%)                                
      Inflammation                                                  2 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Mineralization                                   1 (2%)                                                                       
      Artery, Inflammation, Chronic                    1 (2%)                    1 (2%)                                             
      Epicardium, Fibrosis                                                                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (49)         (50)                                   
      Accessory Adrenal Cortical Nodule                                                       1 (2%)                                
      Angiectasis                                      1 (2%)                                                                       
      Cyst, Focal                                                                1 (2%)                                             
      Degeneration, Cystic, Focal                                   1 (2%)                                                          
      Inflammation                                     1 (2%)                                 1 (2%)                                
      Vacuolization Cytoplasmic                                                  1 (2%)       1 (2%)                                
      Capsule, Hyperplasia                                                       1 (2%)                                             
   Pituitary Gland                                    (48)         (47)         (47)         (48)                                   
      Angiectasis                                      2 (4%)       5 (11%)      1 (2%)       2 (4%)                                
      Pars Distalis, Angiectasis                       1 (2%)                                                                       
      Pars Distalis, Hyperplasia                      12 (25%)      1 (2%)       7 (15%)      6 (13%)                               
   Thyroid Gland                                      (50)         (49)         (49)         (49)                                   
      Cyst                                                                       1 (2%)                                             
      Infiltration Cellular, Lymphocyte                                          1 (2%)                                             
      Inflammation                                                                            1 (2%)                                
      Follicular Cell, Hyperplasia                    20 (40%)     17 (35%)     14 (29%)     19 (39%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (41)         (40)         (43)         (40)                                   
      Cyst                                             1 (2%)                                                                       
      Inflammation                                     1 (2%)       1 (3%)                                                          
   Ovary                                              (48)         (49)         (49)         (48)                                   
      Angiectasis                                      1 (2%)       1 (2%)       1 (2%)                                             
      Atrophy                                                                    2 (4%)                                             
      Cyst                                             9 (19%)     12 (24%)     16 (33%)     15 (31%)                               
      Thrombosis                                                    1 (2%)                                                          
      Bilateral, Cyst                                                            1 (2%)                                             
   Uterus                                             (50)         (50)         (49)         (49)                                   
      Angiectasis                                      1 (2%)       1 (2%)       1 (2%)                                             
      Hydrometra                                                    3 (6%)       3 (6%)       2 (4%)                                
      Hyperplasia, Cystic                             37 (74%)     41 (82%)     38 (78%)     37 (76%)                               
      Inflammation                                                                            2 (4%)                                
      Inflammation, Suppurative                                     1 (2%)                                                          
      Thrombosis                                       1 (2%)                    1 (2%)       1 (2%)                                
      Cervix, Hemorrhage                                            1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (49)         (50)                                   
      Inflammation, Chronic                                                      1 (2%)                                             
   Lymph Node                                         (3)          (6)          (3)          (4)                                    
      Hyperplasia, Lymphoid                                         1 (17%)                                                         
      Iliac, Ectasia                                                             1 (33%)                                            
      Renal, Hyperplasia, Lymphoid                                  1 (17%)                                                         
   Lymph Node, Bronchial                              (30)         (34)         (27)         (35)                                   
      Hyperplasia, Lymphoid                            1 (3%)       2 (6%)       2 (7%)       3 (9%)                                
      Infiltration Cellular, Histiocyte                                                       1 (3%)                                
   Lymph Node, Mandibular                             (37)         (37)         (36)         (36)                                   
      Hyperplasia, Lymphoid                                         1 (3%)                                                          
   Lymph Node, Mesenteric                             (46)         (45)         (46)         (44)                                   
      Hyperplasia, Lymphoid                            1 (2%)       5 (11%)      2 (4%)                                             
      Infiltration Cellular, Histiocyte                1 (2%)                                                                       
      Inflammation, Chronic                            1 (2%)                                                                       
      Necrosis                                                      1 (2%)                                                          
   Lymph Node, Mediastinal                            (41)         (36)         (28)         (34)                                   
      Hemorrhage                                                                              1 (3%)                                
      Hyperplasia, Lymphoid                            3 (7%)       5 (14%)      1 (4%)       3 (9%)                                
   Spleen                                             (50)         (50)         (49)         (49)                                   
      Hematopoietic Cell Proliferation                 3 (6%)      11 (22%)      9 (18%)      3 (6%)                                
      Hyperplasia, Lymphoid                            1 (2%)       5 (10%)      1 (2%)       2 (4%)                                
   Thymus                                             (41)         (44)         (41)         (41)                                   
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                                                          
      Necrosis                                                                   1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (47)         (50)         (50)         (50)                                   
      Hyperplasia                                      3 (6%)       4 (8%)       2 (4%)                                             
   Skin                                               (49)         (50)         (50)         (50)                                   
      Inflammation, Chronic                                         1 (2%)                                                          
      Inflammation, Suppurative                                                  1 (2%)                                             
      Ulcer                                                         1 (2%)       1 (2%)       1 (2%)                                
      Subcutaneous Tissue, Hemorrhage                                            1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Chronic                    1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                           2 (4%)       1 (2%)       1 (2%)       5 (10%)                               
      Fracture                                                                   1 (2%)       1 (2%)                                
      Maxilla, Inflammation, Chronic                                                          1 (2%)                                
   Skeletal Muscle                                                 (1)          (2)          (1)                                    
      Hemorrhage                                                                 1 (50%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Hemorrhage                                                                              1 (2%)                                
   Spinal Cord                                        (1)                                    (1)                                    
      Degeneration                                                                            1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (47)         (50)                                   
      Inflammation, Chronic                                                                   1 (2%)                                
      Metaplasia, Squamous                                         45 (92%)     40 (85%)     50 (100%)                              
   Lung                                               (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       2 (4%)       1 (2%)                    4 (8%)                                
      Infiltration Cellular, Diffuse, Histiocyte                                              4 (8%)                                
      Infiltration Cellular, Focal, Histiocyte         2 (4%)       5 (10%)      7 (14%)     10 (20%)                               
      Inflammation, Chronic                                                      1 (2%)       1 (2%)                                
      Alveolar Epithelium, Hyperplasia                 2 (4%)       3 (6%)                    5 (10%)                               
      Bronchus, Vacuolization Cytoplasmic                           6 (12%)     31 (62%)     43 (86%)                               
      Capillary, Thrombosis, Diffuse                                                          1 (2%)                                
   Nose                                               (50)         (50)         (49)         (48)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Suppurative                                     1 (2%)       5 (10%)      4 (8%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Olfactory Epithelium, Atrophy                                 2 (4%)      12 (24%)     46 (96%)                               
      Olfactory Epithelium, Degeneration, Hyaline      3 (6%)       1 (2%)       2 (4%)       2 (4%)                                
      Olfactory Epithelium, Hyperplasia                                                      30 (63%)                               
      Olfactory Epithelium, Metaplasia                              1 (2%)       1 (2%)                                             
      Respiratory Epithelium, Degeneration, Hyaline   20 (40%)     16 (32%)     14 (29%)     11 (23%)                               
      Respiratory Epithelium, Metaplasia, Squamous                                            4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)                                                                           
      Degeneration                                     1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             1 (2%)                                 2 (4%)                                
      Infarct                                                                                 1 (2%)                                
      Infiltration Cellular, Mixed Cell                3 (6%)       1 (2%)       1 (2%)       3 (6%)                                
      Inflammation, Chronic                                         1 (2%)       1 (2%)                                             
      Metaplasia, Osseous                                           1 (2%)       1 (2%)                                             
      Mineralization                                                                          1 (2%)                                
      Nephropathy                                      5 (10%)      6 (12%)      7 (14%)      3 (6%)                                
      Pigmentation, Hemosiderin                                                               1 (2%)                                
   Urinary Bladder                                    (48)         (47)         (45)         (46)                                   
      Edema                                                         1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                19           16           17           23                                     
    Accidently Killed                                  1                                      1                                     
    Natural Death                                      8            3            9            6                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                22           31           24           20                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (37)         (41)         (38)         (38)                                   
      Degeneration, Hyaline                            1 (3%)       1 (2%)       2 (5%)                                             
      Infiltration Cellular, Lymphocyte                                          1 (3%)                                             
   Intestine Small, Duodenum                          (45)         (49)         (42)         (45)                                   
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Inflammation, Chronic                                                      1 (2%)                                             
      Necrosis, Focal                                                            1 (2%)                                             
   Liver                                              (50)         (50)         (50)         (50)                                   
      Basophilic Focus                                 1 (2%)                                                                       
      Clear Cell Focus                                              3 (6%)       2 (4%)                                             
      Clear Cell Focus, Multiple                                                 1 (2%)                                             
      Cyst                                                                                    1 (2%)                                
      Eosinophilic Focus                               8 (16%)      7 (14%)      9 (18%)      2 (4%)                                
      Eosinophilic Focus, Multiple                     1 (2%)       1 (2%)       3 (6%)                                             
      Infiltration Cellular, Lymphocyte                1 (2%)                                                                       
      Inflammation, Chronic                           33 (66%)     36 (72%)     40 (80%)     39 (78%)                               
      Karyomegaly                                     39 (78%)     35 (70%)     39 (78%)     43 (86%)                               
      Mineralization                                   1 (2%)                                                                       
      Mitotic Alteration                                                                      1 (2%)                                
      Necrosis, Focal                                  3 (6%)       3 (6%)       6 (12%)      1 (2%)                                
      Regeneration                                    32 (64%)     30 (60%)     35 (70%)     38 (76%)                               
      Vacuolization Cytoplasmic, Diffuse                            3 (6%)       1 (2%)                                             
      Vacuolization Cytoplasmic, Focal                                           1 (2%)                                             
      Bile Duct, Hyperplasia                                        3 (6%)       6 (12%)      4 (8%)                                
      Oval Cell, Hyperplasia                          38 (76%)     36 (72%)     40 (80%)     44 (88%)                               
   Mesentery                                          (3)          (4)          (5)          (4)                                    
      Inflammation, Chronic                            1 (33%)                                1 (25%)                               
      Mineralization                                                             1 (20%)                                            
      Artery, Fibrosis                                 1 (33%)                                1 (25%)                               
      Artery, Inflammation, Chronic                                 1 (25%)                                                         
      Fat, Necrosis                                    1 (33%)      2 (50%)      3 (60%)                                            
   Pancreas                                           (48)         (50)         (49)         (50)                                   
      Acinus, Atrophy                                               1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
      Cyst                                                                       1 (2%)                                             
      Hyperplasia, Squamous                            4 (8%)       2 (4%)                    2 (4%)                                
      Inflammation                                                                            1 (2%)                                
   Stomach, Glandular                                 (48)         (50)         (50)         (50)                                   
      Mineralization                                                                          1 (2%)                                
   Tooth                                                                                     (1)                                    
      Inflammation                                                                            1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   1 (2%)       4 (8%)       2 (4%)       1 (2%)                                
      Inflammation, Chronic                                                      1 (2%)                                             
      Artery, Inflammation, Chronic                                              1 (2%)                                             
      Atrium, Thrombosis                               1 (2%)       2 (4%)       3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (50)         (49)         (50)                                   
      Accessory Adrenal Cortical Nodule                                          1 (2%)                                             
      Hyperplasia                                      3 (6%)       4 (8%)       5 (10%)      2 (4%)                                
      Inflammation                                                  1 (2%)                                                          
      Necrosis                                                      1 (2%)                                                          
      Necrosis, Diffuse                                                          1 (2%)                                             
   Adrenal Medulla                                    (48)         (50)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)                                 5 (10%)                               
      Necrosis, Diffuse                                                          1 (2%)                                             
   Thyroid Gland                                      (49)         (50)         (50)         (50)                                   
      Inflammation                                                                            1 (2%)                                
      Follicular Cell, Hyperplasia                     3 (6%)      17 (34%)     11 (22%)     10 (20%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (1)                       (1)                                                 
      Inflammation, Chronic                                                      1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (49)         (50)         (50)         (50)                                   
      Degeneration                                                                            1 (2%)                                
      Granuloma Sperm                                  1 (2%)                                                                       
      Inflammation, Chronic                                                      1 (2%)       2 (4%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Mineralization                                                2 (4%)       1 (2%)                                             
   Penis                                              (1)                                                                           
      Inflammation, Chronic                            1 (100%)                                                                     
   Preputial Gland                                    (49)         (50)         (50)         (49)                                   
      Cyst                                             1 (2%)       2 (4%)       3 (6%)       1 (2%)                                
      Inflammation, Chronic                           13 (27%)     12 (24%)      9 (18%)      5 (10%)                               
      Inflammation, Suppurative                                     2 (4%)       2 (4%)                                             
   Prostate                                           (46)         (50)         (44)         (49)                                   
      Inflammation                                     2 (4%)                    2 (5%)       1 (2%)                                
   Seminal Vesicle                                    (48)         (50)         (49)         (49)                                   
      Inflammation, Chronic                                                      1 (2%)                                             
   Testes                                             (49)         (50)         (50)         (50)                                   
      Atrophy                                                       2 (4%)                    2 (4%)                                
      Degeneration, Focal                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Lymph Node                                         (1)          (1)          (2)          (2)                                    
      Iliac, Hyperplasia, Lymphoid                                  1 (100%)                  1 (50%)                               
      Iliac, Infiltration Cellular, Histiocyte                                   1 (50%)                                            
      Renal, Hyperplasia, Lymphoid                                  1 (100%)                                                        
   Lymph Node, Bronchial                              (21)         (24)         (28)         (25)                                   
      Infiltration Cellular, Plasma Cell                            1 (4%)                                                          
      Infiltration Cellular, Histiocyte                1 (5%)                                 1 (4%)                                
   Lymph Node, Mesenteric                             (49)         (48)         (43)         (47)                                   
      Hematopoietic Cell Proliferation                                           1 (2%)                                             
      Hemorrhage                                       2 (4%)       2 (4%)       4 (9%)       3 (6%)                                
      Hyperplasia, Lymphoid                                         1 (2%)                    2 (4%)                                
      Inflammation, Chronic                            1 (2%)                    2 (5%)       2 (4%)                                
   Lymph Node, Mediastinal                            (43)         (28)         (31)         (35)                                   
      Hyperplasia, Lymphoid                                         1 (4%)       4 (13%)                                            
      Infiltration Cellular, Plasma Cell               1 (2%)       1 (4%)                                                          
      Infiltration Cellular, Histiocyte                2 (5%)                    1 (3%)                                             
      Inflammation, Chronic                                                      1 (3%)       1 (3%)                                
   Spleen                                             (47)         (50)         (49)         (50)                                   
      Angiectasis                                      1 (2%)                                 1 (2%)                                
      Hematopoietic Cell Proliferation                10 (21%)      6 (12%)      6 (12%)     14 (28%)                               
      Hyperplasia, Lymphoid                                         4 (8%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (49)         (50)         (49)         (49)                                   
      Inflammation, Chronic                                         1 (2%)                    2 (4%)                                
      Inflammation, Suppurative                                     1 (2%)                                                          
      Ulcer                                                         1 (2%)       2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Epidermis, Hyperplasia                                                     1 (2%)       1 (2%)                                
      Prepuce, Inflammation, Chronic                                1 (2%)                                                          
      Prepuce, Ulcer                                   4 (8%)       1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fracture                                                                                1 (2%)                                
   Skeletal Muscle                                    (1)                                    (2)                                    
      Inflammation, Chronic, Focal                                                            1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (48)         (49)         (48)         (49)                                   
      Foreign Body                                     1 (2%)                                                                       
      Metaplasia, Squamous                                         37 (76%)     48 (100%)    44 (90%)                               
   Lung                                               (50)         (50)         (50)         (50)                                   
      Hemorrhage                                       1 (2%)                    1 (2%)       1 (2%)                                
      Infiltration Cellular, Diffuse, Histiocyte       1 (2%)       2 (4%)       4 (8%)      10 (20%)                               
      Infiltration Cellular, Focal, Histiocyte        10 (20%)      5 (10%)      8 (16%)     17 (34%)                               
      Inflammation, Chronic                                         1 (2%)       1 (2%)       3 (6%)                                
      Alveolar Epithelium, Hyperplasia                              4 (8%)       4 (8%)       4 (8%)                                
      Alveolar Epithelium, Goblet Cell, Metaplasia,                                                                                 
           Focal                                                    1 (2%)                                                          
      Artery, Thrombosis                                                         1 (2%)                                             
      Bronchus, Hyperplasia                                                      1 (2%)                                             
      Bronchus, Vacuolization Cytoplasmic                          18 (36%)     34 (68%)     38 (76%)                               
   Nose                                               (50)         (50)         (48)         (49)                                   
      Hemorrhage                                                                              1 (2%)                                
      Inflammation, Suppurative                                     1 (2%)                    6 (12%)                               
      Olfactory Epithelium, Atrophy                                             29 (60%)     48 (98%)                               
      Olfactory Epithelium, Degeneration, Hyaline                                2 (4%)       2 (4%)                                
      Olfactory Epithelium, Hyperplasia                                                      10 (20%)                               
      Olfactory Epithelium, Metaplasia                                                        2 (4%)                                
      Respiratory Epithelium, Degeneration, Hyaline                                           1 (2%)                                
   Trachea                                            (49)         (50)         (50)         (50)                                   
      Inflammation, Chronic                            1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05156-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/03/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 10:11:26  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)                       (1)          (1)                                    
      Degeneration                                     1 (100%)                               1 (100%)                              
      Hemorrhage                                                                              1 (100%)                              
      Inflammation                                                                            1 (100%)                              
      Cornea, Inflammation                                                       1 (100%)                                           
   Harderian Gland                                    (4)          (4)          (4)          (6)                                    
      Inflammation, Acute                                           1 (25%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Cyst                                                          1 (2%)                    1 (2%)                                
      Infiltration Cellular, Mixed Cell                5 (10%)      1 (2%)       5 (10%)      3 (6%)                                
      Inflammation, Chronic                            1 (2%)                    1 (2%)                                             
      Metaplasia, Osseous                                                        1 (2%)                                             
      Mineralization                                                                          1 (2%)                                
      Nephropathy                                     11 (22%)     13 (26%)      7 (14%)      9 (18%)                               
      Glomerulus, Amyloid Deposition                                1 (2%)                    2 (4%)                                
      Medulla, Inflammation, Chronic                                                          1 (2%)                                
      Renal Tubule, Hyperplasia                                                               1 (2%)                                
   Urinary Bladder                                    (46)         (49)         (45)         (48)                                   
      Inflammation                                     3 (7%)                    3 (7%)       3 (6%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
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                             ----------              END OF REPORT             ----------                                           
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.