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TDMS Study 05180-06 Pathology Tables

NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24

                                                      2 YEAR CHRONIC RATS




       Facility:  Battelle Northwest

       Chemical CAS #:  1303-00-0000

       Lock Date:  03/13/97

       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: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 


  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                30           30           23           35                                     
    Natural Death                                      1            3            6            4                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                19           17           20           11                                     
    Natural Death                                                                1                                                  

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (49)         (48)         (49)                                   
      Inflammation, Acute                                           1 (2%)                                                          
   Intestine Large, Cecum                             (50)         (49)         (48)         (49)                                   
      Inflammation, Acute                                           1 (2%)                                                          
   Intestine Small, Duodenum                          (50)         (48)         (48)         (49)                                   
      Necrosis                                                      1 (2%)                    2 (4%)                                
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                      2 (4%)       2 (4%)       5 (10%)      3 (6%)                                
      Basophilic Focus                                38 (76%)     36 (72%)     38 (76%)     34 (68%)                               
      Clear Cell Focus                                 5 (10%)      7 (14%)      8 (16%)      2 (4%)                                
      Degeneration, Cystic                                                                    1 (2%)                                
      Eosinophilic Focus                               2 (4%)       3 (6%)       3 (6%)       1 (2%)                                
      Fatty Change                                    12 (24%)     19 (38%)     11 (22%)     12 (24%)                               
      Hepatodiaphragmatic Nodule                       3 (6%)       3 (6%)       3 (6%)       4 (8%)                                
      Inflammation, Granulomatous                      3 (6%)       1 (2%)                    1 (2%)                                
      Mixed Cell Focus                                10 (20%)      9 (18%)      6 (12%)      2 (4%)                                
      Necrosis                                         1 (2%)       1 (2%)       4 (8%)       2 (4%)                                
      Regeneration                                     2 (4%)       1 (2%)                                                          
      Thrombosis                                                                              1 (2%)                                
      Vacuolization Cytoplasmic, Focal                 3 (6%)                    2 (4%)                                             
      Bile Duct, Hyperplasia                          15 (30%)     12 (24%)      7 (14%)     13 (26%)                               
      Centrilobular, Necrosis                          6 (12%)     13 (26%)      8 (16%)     17 (34%)                               
   Mesentery                                          (6)          (14)         (6)          (11)                                   
      Artery, Inflammation, Chronic Active                          1 (7%)                                                          
      Fat, Necrosis                                    6 (100%)    13 (93%)      6 (100%)    11 (100%)                              
   Pancreas                                           (50)         (50)         (50)         (49)                                   
      Atrophy                                         15 (30%)     13 (26%)     21 (42%)     14 (29%)                               
      Basophilic Focus                                 4 (8%)       3 (6%)       1 (2%)       1 (2%)                                
      Hyperplasia                                      3 (6%)                    1 (2%)                                             
      Lipomatosis                                                   1 (2%)                                                          
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                                                            1 (2%)                                
      Hyperplasia, Squamous                                         1 (2%)       1 (2%)       2 (4%)                                

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Mineralization                                                                          1 (2%)                                
      Necrosis                                         4 (8%)       7 (14%)      3 (6%)       4 (8%)                                
   Stomach, Glandular                                 (50)         (50)         (50)         (49)                                   
      Mineralization                                   2 (4%)       1 (2%)       2 (4%)       3 (6%)                                
      Necrosis                                         3 (6%)       6 (12%)      2 (4%)       4 (8%)                                
   Tongue                                                          (1)          (2)                                                 
      Hyperplasia, Squamous                                         1 (100%)     1 (50%)                                            
   Tooth                                              (1)                       (1)                                                 
      Developmental Malformation                                                 1 (100%)                                           
      Inflammation, Chronic Active                     1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                              (1)                                    
      Aorta, Mineralization                                                                   1 (100%)                              
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  34 (68%)     37 (74%)     29 (58%)     31 (62%)                               
      Artery, Mineralization                                                                  1 (2%)                                
      Atrium, Thrombosis                               2 (4%)       3 (6%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (49)                                   
      Degeneration, Cystic                             4 (8%)       2 (4%)       1 (2%)                                             
      Hyperplasia                                     27 (54%)     23 (46%)     25 (50%)     22 (45%)                               
      Hypertrophy                                     10 (20%)     11 (22%)      9 (18%)     11 (22%)                               
      Necrosis                                                      4 (8%)       2 (4%)       2 (4%)                                
      Thrombosis                                                                 1 (2%)                                             
      Vacuolization Cytoplasmic                        2 (4%)       4 (8%)       4 (8%)       3 (6%)                                
   Adrenal Medulla                                    (50)         (49)         (50)         (49)                                   
      Hyperplasia                                     16 (32%)     11 (22%)     15 (30%)     12 (24%)                               
      Bilateral, Hyperplasia                                                     1 (2%)                                             
   Islets, Pancreatic                                 (50)         (50)         (50)         (49)                                   
      Hyperplasia                                                                             1 (2%)                                
   Parathyroid Gland                                  (47)         (42)         (47)         (46)                                   
      Hyperplasia                                                   3 (7%)       3 (6%)       3 (7%)                                
   Pituitary Gland                                    (50)         (50)         (50)         (49)                                   
      Angiectasis                                                                2 (4%)       1 (2%)                                
      Cyst                                             1 (2%)                                                                       
      Pars Distalis, Angiectasis                                                              2 (4%)                                
      Pars Distalis, Hyperplasia                       5 (10%)      3 (6%)       7 (14%)      9 (18%)                               
   Thyroid Gland                                      (50)         (49)         (48)         (49)                                   
      C-Cell, Hyperplasia                             41 (82%)     41 (84%)     38 (79%)     33 (67%)                               
      Follicular Cell, Hyperplasia                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (48)         (47)         (48)                                   
      Hyperplasia                                      2 (4%)       4 (8%)       3 (6%)       2 (4%)                                
      Inflammation, Chronic Active                     2 (4%)       2 (4%)       1 (2%)       2 (4%)                                
      Metaplasia, Squamous                                                                    1 (2%)                                
   Ovary                                              (50)         (50)         (50)         (49)                                   
      Cyst                                             7 (14%)      8 (16%)     10 (20%)      5 (10%)                               
   Uterus                                             (50)         (50)         (49)         (50)                                   
      Hemorrhage                                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (50)         (49)                                   
      Hyperplasia, Histiocytic                                      1 (2%)                                                          
      Inflammation, Granulomatous                      1 (2%)                                                                       
      Myelofibrosis                                    1 (2%)                                                                       
      Necrosis                                                                   1 (2%)                                             
   Lymph Node                                         (3)          (6)          (3)          (5)                                    
      Renal, Hemorrhage                                             1 (17%)      1 (33%)      1 (20%)                               
   Lymph Node, Bronchial                              (36)         (36)         (39)         (40)                                   
      Infiltration Cellular, Plasma Cell               1 (3%)                                                                       
   Lymph Node, Mediastinal                            (34)         (39)         (39)         (39)                                   
      Infiltration Cellular, Polymorphonuclear         1 (3%)                                                                       
   Spleen                                             (50)         (50)         (50)         (49)                                   
      Fibrosis                                         4 (8%)       6 (12%)      5 (10%)      1 (2%)                                
      Hematopoietic Cell Proliferation                 5 (10%)      2 (4%)       6 (12%)      1 (2%)                                
      Hemorrhage                                                                 1 (2%)       2 (4%)                                
      Necrosis                                                      1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (50)         (50)                                   
      Galactocele                                      1 (2%)                    2 (4%)                                             
      Hyperplasia, Atypical                                         1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                           1 (2%)                    1 (2%)       2 (4%)                                
      Hyperostosis                                     7 (14%)      3 (6%)       7 (14%)      9 (18%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (50)         (49)                                   
      Hyperplasia                                      3 (6%)       1 (2%)                    1 (2%)                                
      Inflammation, Chronic Active                     4 (8%)       5 (10%)      3 (6%)       3 (6%)                                
      Metaplasia, Squamous                            10 (20%)      5 (10%)      7 (14%)     11 (22%)                               
      Necrosis                                         1 (2%)                                                                       
      Epiglottis, Hyperplasia                          4 (8%)       2 (4%)                    3 (6%)                                
      Epiglottis, Inflammation, Chronic Active         4 (8%)       1 (2%)       1 (2%)                                             
      Epiglottis, Metaplasia, Squamous                 4 (8%)       6 (12%)      1 (2%)       3 (6%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Cyst, Squamous                                                             1 (2%)                                             
      Hyperplasia, Atypical                                                      9 (18%)     16 (32%)                               
      Inflammation, Chronic Active                    11 (22%)     46 (92%)     49 (98%)     50 (100%)                              
      Metaplasia, Squamous                                                       2 (4%)       1 (2%)                                
      Mineralization                                   1 (2%)                                 1 (2%)                                
      Proteinosis                                      1 (2%)      24 (48%)     47 (94%)     49 (98%)                               
      Thrombosis                                                    1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia                14 (28%)      9 (18%)     17 (34%)     14 (28%)                               
      Alveolar Epithelium, Metaplasia                               1 (2%)      36 (72%)     41 (82%)                               
      Artery, Mediastinum, Inflammation                             1 (2%)                                                          
      Artery, Mediastinum, Mineralization                                                     1 (2%)                                
   Nose                                               (50)         (50)         (49)         (49)                                   
      Hemorrhage                                                                 1 (2%)                                             
      Inflammation, Suppurative                        3 (6%)       4 (8%)       9 (18%)      3 (6%)                                
      Thrombosis                                       2 (4%)       7 (14%)      4 (8%)       6 (12%)                               
      Olfactory Epithelium, Atrophy                                                           2 (4%)                                
      Olfactory Epithelium, Degeneration, Hyaline     39 (78%)     38 (76%)     33 (67%)     32 (65%)                               
      Olfactory Epithelium, Metaplasia, Respiratory                 2 (4%)       2 (4%)       1 (2%)                                
      Respiratory Epithelium, Hyperplasia              1 (2%)                                                                       
      Respiratory Epithelium, Metaplasia, Squamous                               1 (2%)                                             
   Trachea                                            (50)         (50)         (50)         (49)                                   
      Mineralization                                                                          1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS FEMALE                   CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (5)          (6)          (1)                                    
      Cataract                                         1 (100%)     4 (80%)      1 (17%)      1 (100%)                              
      Degeneration                                                  1 (20%)      4 (67%)                                            
      Retina, Atrophy                                  1 (100%)     4 (80%)      1 (17%)      1 (100%)                              
      Sclera, Inflammation, Acute                                                1 (17%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (49)                                   
      Amyloid Deposition                               1 (2%)                                                                       
      Angiectasis                                                                             1 (2%)                                
      Cyst                                                          1 (2%)       2 (4%)                                             
      Hydronephrosis                                                             1 (2%)                                             
      Infarct                                                       3 (6%)       1 (2%)       1 (2%)                                
      Inflammation, Suppurative                        1 (2%)                                                                       
      Mineralization                                                                          1 (2%)                                
      Nephropathy                                     48 (96%)     47 (94%)     47 (94%)     45 (92%)                               
      Thrombosis                                                                              1 (2%)                                
      Renal Tubule, Hyperplasia                        2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Renal Tubule, Necrosis                           1 (2%)       1 (2%)                                                          
      Transitional Epithelium, Hyperplasia                          1 (2%)                                                          
   Urinary Bladder                                    (50)         (50)         (50)         (49)                                   
      Hemorrhage                                                    1 (2%)                                                          
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________

DISPOSITION SUMMARY                                                                                                                 


  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                30           29           32           33                                     
    Natural Death                                      7            8            3            4                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                13           13           15           13                                     

  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (47)         (47)         (48)         (50)                                   
      Mineralization                                                1 (2%)                                                          
   Intestine Large, Rectum                            (48)         (49)         (47)         (49)                                   
      Inflammation, Acute                              1 (2%)                                                                       
      Mineralization                                                1 (2%)                                                          
      Anus, Hyperplasia                                                                       1 (2%)                                
   Intestine Large, Cecum                             (46)         (43)         (48)         (49)                                   
      Inflammation, Acute                              1 (2%)       1 (2%)                                                          
      Mineralization                                                3 (7%)                                                          
      Necrosis                                                      1 (2%)                    1 (2%)                                
   Intestine Small, Duodenum                          (48)         (48)         (49)         (50)                                   
      Inflammation, Acute                                           1 (2%)                    1 (2%)                                
      Necrosis                                                                   2 (4%)                                             
   Intestine Small, Ileum                             (44)         (43)         (48)         (49)                                   
      Inflammation, Granulomatous                      1 (2%)                                                                       
      Mineralization                                   1 (2%)                                 1 (2%)                                
   Liver                                              (50)         (50)         (50)         (50)                                   
      Angiectasis                                                   2 (4%)                    5 (10%)                               
      Basophilic Focus                                21 (42%)     23 (46%)     21 (42%)     15 (30%)                               
      Clear Cell Focus                                 6 (12%)      3 (6%)       6 (12%)      9 (18%)                               
      Degeneration, Cystic                            10 (20%)      9 (18%)     10 (20%)     10 (20%)                               
      Eosinophilic Focus                               6 (12%)      4 (8%)       5 (10%)      4 (8%)                                
      Fatty Change                                     5 (10%)      8 (16%)      8 (16%)      7 (14%)                               
      Hepatodiaphragmatic Nodule                       1 (2%)       2 (4%)       3 (6%)       2 (4%)                                
      Inflammation, Granulomatous                      1 (2%)                                                                       
      Mineralization                                                             1 (2%)                                             
      Mixed Cell Focus                                 1 (2%)                                                                       
      Necrosis                                         2 (4%)                    4 (8%)       1 (2%)                                
      Regeneration                                     1 (2%)       4 (8%)       5 (10%)                                            
      Vacuolization Cytoplasmic, Focal                 1 (2%)                                                                       
      Bile Duct, Hyperplasia                          28 (56%)     27 (54%)     32 (64%)     30 (60%)                               
      Bile Duct, Inflammation, Acute                                             2 (4%)                                             
      Centrilobular, Necrosis                         13 (26%)     14 (28%)     16 (32%)     13 (26%)                               
   Mesentery                                          (5)          (10)         (14)         (7)                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hemorrhage                                                    1 (10%)      1 (7%)                                             
      Artery, Inflammation, Chronic Active                          1 (10%)                                                         
      Artery, Mineralization                           3 (60%)      2 (20%)      2 (14%)      2 (29%)                               
      Fat, Inflammation                                                          1 (7%)                                             
      Fat, Necrosis                                    3 (60%)      7 (70%)     11 (79%)      5 (71%)                               
   Oral Mucosa                                        (1)          (3)                       (1)                                    
      Pharyngeal, Inflammation, Chronic                1 (100%)                                                                     
   Pancreas                                           (49)         (49)         (50)         (50)                                   
      Atrophy                                         24 (49%)     29 (59%)     25 (50%)     27 (54%)                               
      Basophilic Focus                                 3 (6%)       3 (6%)       2 (4%)       3 (6%)                                
      Hyperplasia                                      4 (8%)       3 (6%)       2 (4%)       1 (2%)                                
      Inflammation, Acute                                                        1 (2%)                                             
      Metaplasia, Hepatocyte                                                     1 (2%)                                             
      Artery, Inflammation                             2 (4%)                                 1 (2%)                                
      Artery, Mineralization                           3 (6%)       2 (4%)       1 (2%)       1 (2%)                                
      Duct, Hyperplasia                                                          1 (2%)                                             
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)                    1 (2%)                                             
      Artery, Mineralization                           1 (2%)                                                                       
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
      Hyperplasia, Squamous                                                      1 (2%)                                             
      Inflammation, Acute                                                                     1 (2%)                                
      Mineralization                                   2 (4%)       2 (4%)       2 (4%)       2 (4%)                                
      Necrosis                                         7 (14%)     10 (20%)      9 (18%)     11 (22%)                               
   Stomach, Glandular                                 (49)         (49)         (50)         (50)                                   
      Inflammation, Acute                              1 (2%)                                                                       
      Mineralization                                   8 (16%)      6 (12%)      8 (16%)      8 (16%)                               
      Necrosis                                         4 (8%)       9 (18%)     13 (26%)     13 (26%)                               
   Tooth                                              (2)          (1)                       (3)                                    
      Developmental Malformation                       2 (100%)     1 (100%)                  3 (100%)                              
      Inflammation, Chronic Active                     1 (50%)                                1 (33%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (3)          (4)          (6)          (6)                                    
      Aorta, Mineralization                            3 (100%)     4 (100%)     4 (67%)      6 (100%)                              
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  44 (88%)     37 (74%)     41 (82%)     40 (80%)                               
      Necrosis                                                                                1 (2%)                                
      Artery, Inflammation, Chronic                                              1 (2%)                                             
      Artery, Mineralization                           5 (10%)      6 (12%)      5 (10%)      7 (14%)                               
      Atrium, Thrombosis                               4 (8%)       1 (2%)       3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (49)         (49)         (50)                                   
      Atrophy                                          1 (2%)                                 1 (2%)                                
      Degeneration, Cystic                                                       1 (2%)                                             
      Hyperplasia                                     24 (49%)     24 (49%)     23 (47%)     23 (46%)                               
      Hypertrophy                                      1 (2%)       3 (6%)       3 (6%)       2 (4%)                                
      Mineralization                                                1 (2%)                                                          
      Necrosis                                         1 (2%)                    4 (8%)       3 (6%)                                
      Vacuolization Cytoplasmic                        2 (4%)       5 (10%)      2 (4%)       1 (2%)                                
   Adrenal Medulla                                    (50)         (49)         (49)         (50)                                   
      Hyperplasia                                     22 (44%)     25 (51%)     22 (45%)     26 (52%)                               
      Bilateral, Hyperplasia                                        1 (2%)       1 (2%)       7 (14%)                               
   Islets, Pancreatic                                 (48)         (49)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)       2 (4%)       2 (4%)       4 (8%)                                
   Parathyroid Gland                                  (47)         (48)         (47)         (48)                                   
      Hyperplasia                                     13 (28%)     13 (27%)     17 (36%)     16 (33%)                               
   Pituitary Gland                                    (49)         (49)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)                    1 (2%)                                
      Pars Distalis, Hyperplasia                      17 (35%)     12 (24%)     15 (30%)     12 (24%)                               
   Thyroid Gland                                      (46)         (46)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)                                                                       
      C-Cell, Hyperplasia                             26 (57%)     28 (61%)     33 (67%)     29 (58%)                               
      Follicular Cell, Hyperplasia                                  1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                               (1)                                                              
      Hyperplasia, Atypical                                         1 (100%)                                                        
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Atrophy                                                                    1 (2%)                                             
      Granuloma Sperm                                                                         3 (6%)                                
   Preputial Gland                                    (50)         (49)         (50)         (49)                                   
      Hyperplasia                                      1 (2%)                    3 (6%)       4 (8%)                                
      Inflammation, Chronic Active                     4 (8%)       4 (8%)       8 (16%)      3 (6%)                                
   Prostate                                           (50)         (48)         (50)         (50)                                   
      Hyperplasia                                     12 (24%)      9 (19%)     11 (22%)      7 (14%)                               
      Inflammation, Chronic Active                     3 (6%)       1 (2%)       6 (12%)      2 (4%)                                
      Mineralization                                   1 (2%)                                                                       
   Seminal Vesicle                                    (45)         (47)         (48)         (50)                                   
      Inflammation, Chronic Active                                               1 (2%)                                             
      Mineralization                                   2 (4%)       1 (2%)       1 (2%)                                             

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)       2 (4%)       5 (10%)      5 (10%)                               
      Artery, Inflammation, Chronic Active             3 (6%)       4 (8%)       5 (10%)      4 (8%)                                
      Interstitial Cell, Hyperplasia                   2 (4%)       3 (6%)       2 (4%)       6 (12%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (48)         (50)         (50)                                   
      Thrombosis                                                                 1 (2%)                                             
   Lymph Node                                         (12)         (8)          (9)          (5)                                    
      Hemorrhage                                       1 (8%)                                                                       
      Renal, Ectasia                                   1 (8%)                                                                       
      Renal, Hemorrhage                                1 (8%)                                                                       
      Renal, Infiltration Cellular, Plasma Cell                     1 (13%)                                                         
   Lymph Node, Mandibular                             (46)         (43)         (46)         (44)                                   
      Infiltration Cellular, Plasma Cell               2 (4%)       1 (2%)       1 (2%)       3 (7%)                                
      Infiltration Cellular, Polymorphonuclear         1 (2%)                                                                       
      Inflammation, Chronic Active                                               1 (2%)                                             
   Lymph Node, Mesenteric                             (48)         (48)         (50)         (48)                                   
      Hemorrhage                                       1 (2%)                                                                       
   Lymph Node, Mediastinal                            (42)         (40)         (46)         (47)                                   
      Hemorrhage                                       1 (2%)                                                                       
      Infiltration Cellular, Plasma Cell                                                      1 (2%)                                
      Infiltration Cellular, Polymorphonuclear                                   1 (2%)                                             
      Pigmentation                                                                            1 (2%)                                
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Congestion                                       1 (2%)                                                                       
      Fibrosis                                        13 (26%)     12 (24%)     17 (34%)     12 (24%)                               
      Hematopoietic Cell Proliferation                 4 (8%)       2 (4%)       6 (12%)      1 (2%)                                
      Hyperplasia                                                   1 (2%)       1 (2%)                                             
      Inflammation, Acute                                                        1 (2%)                                             
      Inflammation, Granulomatous                      2 (4%)                                                                       
      Necrosis                                                      1 (2%)       5 (10%)                                            
      Thrombosis                                       1 (2%)                                                                       
   Thymus                                             (46)         (45)         (45)         (42)                                   
      Cyst                                             1 (2%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (41)         (42)         (42)         (40)                                   
      Galactocele                                      1 (2%)       2 (5%)       1 (2%)       3 (8%)                                
   Skin                                               (50)         (49)         (50)         (50)                                   
      Hyperkeratosis                                   1 (2%)                    2 (4%)                                             
      Inflammation, Chronic Active                                               3 (6%)       2 (4%)                                
____________________________________________________________________________________________________________________________________

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Callus                                                        1 (2%)                                                          
      Fibrous Osteodystrophy                           8 (16%)      9 (18%)     10 (20%)     11 (22%)                               
      Hyperostosis                                                                            1 (2%)                                
      Inflammation, Chronic Active                                                            1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Degeneration                                     1 (2%)                                                                       
      Gliosis                                                       1 (2%)                                                          
      Hemorrhage                                                                              1 (2%)                                
      Mineralization                                                                          1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (49)         (50)                                   
      Hyperplasia                                      3 (6%)       8 (16%)      4 (8%)      11 (22%)                               
      Inflammation, Chronic Active                     4 (8%)       3 (6%)       4 (8%)      12 (24%)                               
      Metaplasia, Squamous                             1 (2%)       2 (4%)       2 (4%)      10 (20%)                               
      Mineralization                                   1 (2%)                    3 (6%)       1 (2%)                                
      Epiglottis, Hyperplasia                                       6 (12%)      4 (8%)       5 (10%)                               
      Epiglottis, Inflammation, Chronic Active                      1 (2%)       2 (4%)       4 (8%)                                
      Epiglottis, Metaplasia, Squamous                                                        3 (6%)                                
      Epiglottis, Mineralization                                                              1 (2%)                                
   Lung                                               (50)         (49)         (50)         (50)                                   
      Cyst, Squamous                                                                          1 (2%)                                
      Hemorrhage                                       1 (2%)       1 (2%)                                                          
      Hyperplasia, Atypical                                         2 (4%)       5 (10%)     18 (36%)                               
      Inflammation, Chronic Active                     3 (6%)      43 (88%)     50 (100%)    50 (100%)                              
      Metaplasia, Squamous                                                       1 (2%)       2 (4%)                                
      Mineralization                                   4 (8%)       5 (10%)      3 (6%)       7 (14%)                               
      Proteinosis                                                  22 (45%)     50 (100%)    49 (98%)                               
      Thrombosis                                       1 (2%)                                 2 (4%)                                
      Alveolar Epithelium, Hyperplasia                12 (24%)     16 (33%)     21 (42%)     21 (42%)                               
      Alveolar Epithelium, Metaplasia                               2 (4%)      34 (68%)     41 (82%)                               
      Artery, Mediastinum, Mineralization              4 (8%)       3 (6%)       2 (4%)       5 (10%)                               
   Nose                                               (50)         (48)         (49)         (50)                                   
      Inflammation, Suppurative                       10 (20%)      5 (10%)     10 (20%)      8 (16%)                               
      Polyp Inflammatory                                                         1 (2%)                                             
      Thrombosis                                       4 (8%)       8 (17%)      8 (16%)      7 (14%)                               
      Olfactory Epithelium, Atrophy                    1 (2%)       2 (4%)       1 (2%)       2 (4%)                                
      Olfactory Epithelium, Degeneration, Hyaline     18 (36%)     26 (54%)     32 (65%)     25 (50%)                               

a  Number of animals examined microscopically at site and number of animals with lesion                                             
NTP Experiment-Test: 05180-06         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          GALLIUM ARSENIDE                                     Date: 02/17/99  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 08:09:24  
____________________________________________________________________________________________________________________________________

         FISCHER 344 RATS MALE                     CONTROL      0.01         0.1          1.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Olfactory Epithelium, Metaplasia, Respiratory    2 (4%)       2 (4%)       1 (2%)       2 (4%)                                
      Respiratory Epithelium, Degeneration, Hyaline                                           1 (2%)                                
      Respiratory Epithelium, Metaplasia, Squamous                                            1 (2%)                                
      Turbinate, Necrosis                                                                     1 (2%)                                
   Trachea                                            (49)         (50)         (49)         (50)                                   
      Mineralization                                   2 (4%)                    2 (4%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (4)          (2)          (1)          (1)                                    
      Cataract                                         4 (100%)     1 (50%)                   1 (100%)                              
      Degeneration                                                               1 (100%)                                           
      Retina, Atrophy                                  4 (100%)     1 (50%)                   1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Cyst                                             3 (6%)       3 (6%)       1 (2%)       1 (2%)                                
      Infarct                                                       2 (4%)       1 (2%)       2 (4%)                                
      Mineralization                                   5 (10%)      4 (8%)       5 (10%)      4 (8%)                                
      Nephropathy                                     48 (98%)     49 (98%)     50 (100%)    50 (100%)                              
      Renal Tubule, Hyperplasia                        2 (4%)       1 (2%)       4 (8%)       2 (4%)                                
   Urinary Bladder                                    (48)         (50)         (50)         (50)                                   
      Hemorrhage                                                    2 (4%)                                                          
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Transitional Epithelium, Hyperplasia             1 (2%)                                                                       
                                                                                                                                    

a  Number of animals examined microscopically at site and number of animals with lesion                                             
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------