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TDMS Study 60968-02 Pathology Tables

NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  0078-84-2

       Lock Date:  05/12/94

       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: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                16           13           11           11                                     
    Natural Death                                      5            4            3            2                                     
    Accidently Killed                                  1            1                                                               
  Survivors                                                                                                                         
    Terminal Sacrifice                                28           32           35           37                                     
    Natural Death                                                                1                                                  
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (46)         (44)         (45)         (47)                                   
      Hyperplasia                                                   1 (2%)                    1 (2%)                                
   Intestine Small, Ileum                             (49)         (46)         (47)         (49)                                   
      Hyperplasia, Lymphoid                            1 (2%)                    1 (2%)                                             
   Liver                                              (49)         (49)         (50)         (50)                                   
      Angiectasis                                                                2 (4%)                                             
      Basophilic Focus                                 1 (2%)       3 (6%)       2 (4%)       3 (6%)                                
      Clear Cell Focus                                 1 (2%)                    2 (4%)                                             
      Cyst                                                          1 (2%)       1 (2%)                                             
      Eosinophilic Focus                               6 (12%)      7 (14%)      5 (10%)      4 (8%)                                
      Hematopoietic Cell Proliferation                              1 (2%)                    1 (2%)                                
      Mixed Cell Focus                                                           1 (2%)                                             
      Necrosis                                         4 (8%)       3 (6%)       1 (2%)       1 (2%)                                
      Tension Lipidosis                                3 (6%)                    2 (4%)                                             
      Thrombosis                                                    1 (2%)                                                          
      Centrilobular, Necrosis                          1 (2%)       2 (4%)       2 (4%)                                             
   Mesentery                                          (8)          (2)          (4)          (3)                                    
      Hemorrhage                                                                              1 (33%)                               
      Fat, Necrosis                                    6 (75%)      2 (100%)                  2 (67%)                               
   Pancreas                                           (50)         (49)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                 1 (2%)                                
      Basophilic Focus                                 1 (2%)                                                                       
      Cyst                                             2 (4%)       1 (2%)                    1 (2%)                                
      Hypertrophy                                                                1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)                    1 (2%)       2 (4%)                                
      Lipomatosis                                      4 (8%)       1 (2%)       3 (6%)       3 (6%)                                
      Thrombosis                                       1 (2%)                                                                       
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                                                            1 (2%)                                
      Hyperplasia, Squamous                            1 (2%)       1 (2%)                    3 (6%)                                
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
   Stomach, Glandular                                 (49)         (49)         (50)         (50)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Inflammation, Chronic Active                                               1 (2%)                                             
      Mineralization                                                1 (2%)                                                          
   Tooth                                                                                     (1)                                    
      Developmental Malformation                                                              1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                   9 (18%)     12 (24%)     10 (20%)      7 (14%)                               
      Artery, Mineralization                                        1 (2%)                                                          
      Atrium, Thrombosis                               1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (49)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                                                       
      Degeneration, Fatty                              2 (4%)       2 (4%)       1 (2%)       1 (2%)                                
      Hyperplasia                                      5 (10%)      3 (6%)                    1 (2%)                                
      Hypertrophy                                                                1 (2%)       1 (2%)                                
      Necrosis                                                                   1 (2%)                                             
   Adrenal Medulla                                    (50)         (49)         (50)         (50)                                   
      Hyperplasia                                      5 (10%)      3 (6%)       2 (4%)       1 (2%)                                
   Pituitary Gland                                    (50)         (49)         (50)         (49)                                   
      Pars Distalis, Hyperplasia                      19 (38%)     23 (47%)     23 (46%)     17 (35%)                               
      Pars Intermedia, Hyperplasia                                               1 (2%)                                             
      Pars Intermedia, Hypertrophy                     1 (2%)                                 1 (2%)                                
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Follicular Cell, Hyperplasia                    18 (36%)     26 (52%)     24 (48%)     32 (64%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (44)         (39)         (40)         (40)                                   
      Inflammation, Chronic Active                                  1 (3%)                                                          
   Ovary                                              (50)         (49)         (50)         (50)                                   
      Angiectasis                                                                2 (4%)                                             
      Cyst                                            13 (26%)     15 (31%)     14 (28%)     18 (36%)                               
      Hyperplasia                                                                             1 (2%)                                
      Interstitial Cell, Hyperplasia                                                          1 (2%)                                
   Uterus                                             (50)         (50)         (50)         (50)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Angiectasis                                      2 (4%)                                 1 (2%)                                
      Hemorrhage                                                                 1 (2%)                                             
      Hydrometra                                       4 (8%)       4 (8%)       6 (12%)      7 (14%)                               
      Inflammation, Suppurative                                     1 (2%)                                                          
      Thrombosis                                                                              1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Lymph Node                                         (5)          (5)          (4)          (4)                                    
      Lumbar, Ectasia                                                            1 (25%)                                            
      Lumbar, Hemorrhage                                                                      1 (25%)                               
   Lymph Node, Bronchial                              (42)         (38)         (42)         (44)                                   
      Hemorrhage                                       1 (2%)                                                                       
   Lymph Node, Mesenteric                             (48)         (49)         (47)         (47)                                   
      Angiectasis                                                                             1 (2%)                                
      Necrosis                                                                   1 (2%)                                             
   Spleen                                             (50)         (49)         (50)         (50)                                   
      Congestion                                       1 (2%)                                                                       
      Hematopoietic Cell Proliferation                11 (22%)     11 (22%)     11 (22%)      9 (18%)                               
      Hyperplasia, Lymphoid                            2 (4%)       2 (4%)       3 (6%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Acute                              1 (2%)                                                                       
      Inflammation, Chronic Active                                                            1 (2%)                                
      Subcutaneous Tissue, Angiectasis                                           1 (2%)                                             
      Subcutaneous Tissue, Necrosis                                                           1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fracture                                                      1 (2%)                                                          
      Hyperostosis                                                               1 (2%)                                             
   Skeletal Muscle                                                 (1)          (1)                                                 
      Hemorrhage                                                    1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Meninges, Infiltration Cellular, Mononuclear                                                                                  
          Cell                                                                                1 (2%)                                
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (50)         (49)         (50)                                   
      Inflammation, Suppurative                                                  1 (2%)                                             
      Epiglottis, Hyperplasia                                                                 1 (2%)                                
      Epiglottis, Metaplasia, Squamous                                                        1 (2%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Congestion, Chronic                              1 (2%)                                                                       
      Hemorrhage                                       1 (2%)       1 (2%)                                                          
      Inflammation, Suppurative                        1 (2%)                                                                       
      Mineralization                                                                          1 (2%)                                
      Thrombosis                                                    1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia                 3 (6%)       3 (6%)                    1 (2%)                                
      Alveolus, Infiltration Cellular, Histiocyte      2 (4%)       2 (4%)       1 (2%)                                             
      Bronchiole, Hyperplasia                          1 (2%)                                                                       
      Interstitium, Fibrosis                           1 (2%)                                                                       
   Nose                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                        1 (2%)       1 (2%)       1 (2%)                                             
      Thrombosis                                                    1 (2%)                                                          
      Olfactory Epithelium, Degeneration               1 (2%)       1 (2%)      27 (54%)     49 (98%)                               
      Olfactory Epithelium, Degeneration, Hyaline                                1 (2%)                                             
      Olfactory Epithelium, Necrosis                                             2 (4%)       1 (2%)                                
      Respiratory Epithelium, Necrosis                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                                                       (3)                                    
      Cornea, Mineralization                                                                  2 (67%)                               
      Lens, Mineralization                                                                    1 (33%)                               
   Harderian Gland                                    (3)          (4)          (2)          (2)                                    
      Hyperplasia                                                                             1 (50%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Amyloid Deposition                               2 (4%)       1 (2%)                                                          
      Atrophy                                                                    1 (2%)                                             
      Cyst                                             1 (2%)                    1 (2%)                                             
      Infarct                                          1 (2%)       2 (4%)                    2 (4%)                                
      Metaplasia, Osseous                                           1 (2%)       4 (8%)       1 (2%)                                
      Mineralization                                                1 (2%)       2 (4%)                                             
      Nephropathy                                     23 (46%)     20 (40%)     15 (30%)     20 (40%)                               
      Pelvis, Dilatation                                                         1 (2%)                                             
      Pelvis, Inflammation, Acute                      1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE FEMALE                        CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Renal Tubule, Necrosis                                        1 (2%)       1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 6            8            6           15                                     
    Natural Death                                      4            5            9            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                40           37           35           30                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (47)         (43)         (42)         (44)                                   
      Hyperplasia                                      1 (2%)       2 (5%)       2 (5%)                                             
   Intestine Large, Cecum                             (49)         (48)         (48)         (48)                                   
      Fibrosis                                                      1 (2%)                                                          
      Parasite Metazoan                                                          1 (2%)                                             
   Liver                                              (49)         (50)         (50)         (50)                                   
      Angiectasis                                                   1 (2%)                                                          
      Basophilic Focus                                 4 (8%)       8 (16%)      3 (6%)       4 (8%)                                
      Clear Cell Focus                                 2 (4%)       7 (14%)      3 (6%)       2 (4%)                                
      Cyst                                                                                    1 (2%)                                
      Degeneration, Fatty                                                        1 (2%)                                             
      Eosinophilic Focus                               3 (6%)       6 (12%)      3 (6%)       3 (6%)                                
      Infarct, Focal                                   1 (2%)                    2 (4%)                                             
      Mixed Cell Focus                                              2 (4%)                    1 (2%)                                
      Necrosis                                         1 (2%)       1 (2%)       1 (2%)       2 (4%)                                
      Tension Lipidosis                                                          1 (2%)                                             
      Centrilobular, Necrosis                                       1 (2%)       1 (2%)                                             
   Mesentery                                          (1)          (3)          (5)          (3)                                    
      Artery, Inflammation                                          1 (33%)                                                         
      Fat, Necrosis                                    1 (100%)     2 (67%)      4 (80%)      2 (67%)                               
   Pancreas                                           (50)         (49)         (50)         (50)                                   
      Atrophy                                          1 (2%)                    1 (2%)                                             
      Cyst                                                                                    1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)                                 1 (2%)                                
      Lipomatosis                                      2 (4%)       2 (4%)       2 (4%)       5 (10%)                               
      Necrosis                                         1 (2%)                                                                       
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Diverticulum                                     1 (2%)                                                                       
      Inflammation, Chronic Active                     2 (4%)       2 (4%)       2 (4%)       1 (2%)                                
   Stomach, Glandular                                 (50)         (50)         (49)         (50)                                   
      Inflammation, Chronic Active                                  1 (2%)       2 (4%)       1 (2%)                                
      Artery, Inflammation                                                       1 (2%)                                             
   Tooth                                                           (3)          (2)                                                 
      Developmental Malformation                                    3 (100%)     1 (50%)                                            
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  26 (52%)     30 (60%)     26 (52%)     27 (54%)                               
      Inflammation, Suppurative                                                               1 (2%)                                
      Mineralization                                                             1 (2%)                                             
      Atrium, Thrombosis                                                         1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Atrophy                                          1 (2%)                                                                       
      Hyperplasia                                     14 (28%)     21 (42%)     18 (36%)     18 (36%)                               
      Hypertrophy                                     32 (64%)     21 (42%)     26 (52%)     26 (52%)                               
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Hyperplasia                                      1 (2%)                    1 (2%)                                             
   Pituitary Gland                                    (49)         (47)         (49)         (49)                                   
      Cyst                                                                       1 (2%)                                             
      Pars Distalis, Hyperplasia                       3 (6%)       3 (6%)                                                          
      Pars Intermedia, Hyperplasia                                               1 (2%)       1 (2%)                                
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Follicular Cell, Hyperplasia                    11 (22%)     11 (22%)     14 (28%)     12 (24%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  1 (2%)                                                                       
   Penis                                                                        (1)          (2)                                    
      Inflammation, Chronic Active                                                            1 (50%)                               
   Preputial Gland                                    (50)         (50)         (49)         (50)                                   
      Cyst                                             7 (14%)      9 (18%)      6 (12%)      4 (8%)                                
      Inflammation, Chronic Active                     1 (2%)       2 (4%)       3 (6%)       5 (10%)                               
   Prostate                                           (49)         (50)         (47)         (48)                                   
      Hyperplasia                                                                1 (2%)                                             
      Inflammation, Chronic Active                     1 (2%)       1 (2%)       2 (4%)                                             
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
      Inflammation, Acute                              1 (2%)                    1 (2%)                                             
      Inflammation, Chronic Active                     2 (4%)       1 (2%)                                                          
   Testes                                             (50)         (50)         (50)         (50)                                   
      Degeneration                                     1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Lymph Node                                                                                (4)                                    
      Iliac, Infiltration Cellular, Plasma Cell                                               1 (25%)                               
   Lymph Node, Mesenteric                             (50)         (48)         (47)         (47)                                   
      Angiectasis                                                                             1 (2%)                                
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Angiectasis                                                                1 (2%)                                             
      Hematopoietic Cell Proliferation                 7 (14%)      7 (14%)      8 (16%)      9 (18%)                               
      Hyperplasia, Lymphoid                            1 (2%)       1 (2%)                    1 (2%)                                
   Thymus                                             (39)         (39)         (42)         (36)                                   
      Artery, Inflammation                                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (49)         (50)         (50)         (50)                                   
      Inflammation, Chronic Active                     1 (2%)       2 (4%)       2 (4%)                                             
      Necrosis                                                      1 (2%)                                                          
      Prepuce, Inflammation, Acute                     3 (6%)       4 (8%)       4 (8%)       9 (18%)                               
      Subcutaneous Tissue, Edema                                                 1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Cyst Epithelial Inclusion                                                               1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (50)         (50)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
      Epiglottis, Hyperplasia                          1 (2%)                    1 (2%)                                             
      Epiglottis, Metaplasia, Squamous                 1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
      Glands, Inflammation, Suppurative                             1 (2%)       1 (2%)       3 (6%)                                
   Lung                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
      Mineralization                                   1 (2%)                                                                       
      Pigmentation                                     1 (2%)                                                                       
      Alveolar Epithelium, Hyperplasia                 3 (6%)       3 (6%)       3 (6%)       2 (4%)                                
      Alveolus, Infiltration Cellular, Histiocyte                                1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 60968-02         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 09/23/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:07:05  
____________________________________________________________________________________________________________________________________
         B6C3F1 MICE MALE                          CONTROL      500 PPM      1000 PPM     2000 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Artery, Mediastinum, Mineralization              1 (2%)       1 (2%)                                                          
      Bronchiole, Hyperplasia                          2 (4%)                                                                       
   Nose                                               (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                     2 (4%)       1 (2%)       3 (6%)                                
      Nasolacrimal Duct, Hyperplasia                   1 (2%)                                                                       
      Nasolacrimal Duct, Inflammation, Suppurative     1 (2%)                                                                       
      Olfactory Epithelium, Degeneration                                        11 (22%)     45 (90%)                               
      Olfactory Epithelium, Necrosis                                                          1 (2%)                                
   Trachea                                            (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                     1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                                          (1)                                                 
      Cornea, Inflammation, Chronic Active                                       1 (100%)                                           
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 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Cyst                                             3 (6%)       3 (6%)       1 (2%)       1 (2%)                                
      Infarct                                          2 (4%)       1 (2%)       1 (2%)       5 (10%)                               
      Mineralization                                   1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Necrosis                                                                                1 (2%)                                
      Nephropathy                                     45 (90%)     46 (92%)     44 (88%)     45 (90%)                               
      Artery, Inflammation                                                                    2 (4%)                                
      Pelvis, Dilatation                                                         1 (2%)                                             
      Pelvis, Inflammation, Acute                      2 (4%)       1 (2%)       2 (4%)       2 (4%)                                
      Transitional Epithelium, Hyperplasia                                       1 (2%)                                             
   Urinary Bladder                                    (50)         (50)         (48)         (50)                                   
      Inflammation, Acute                                                                     1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)                    2 (4%)       3 (6%)                                
      Mineralization                                   1 (2%)                                                                       
      Artery, Inflammation                                                       1 (2%)                                             
      Transitional Epithelium, Hyperplasia             1 (2%)                                 1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
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