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TDMS Study 97006-02 Pathology Tables

NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48

                                                          FINAL#1 MICE




       Facility:  Battelle Northwest

       Chemical CAS #:  108-10-1

       Lock Date:  01/24/03

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All




































                                                              Page   1


NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 2| 3| 9| 1| 3| 3| 7| 3| 3| 3| 3| 3| 8| 9| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|             
                                           | 3| 4| 2| 1| 5| 2| 2| 8| 2| 3| 3| 3| 2| 6| 7| 3| 2| 3| 1| 3| 3| 5| 1| 2| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  A  +  +  A  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |       X                    X                                         X   |             
      Clear Cell Focus                     |                   X                                                      |             
      Eosinophilic Focus                   | X     X                       X                                X         |             
      Infiltration Cellular, Mast Cell     |    2                                                                     |             
      Mixed Cell Focus                     |                               X                                          |             
      Necrosis                             |    3                                                                     |             
      Tension Lipidosis                    |                                              1                           |             
      Thrombosis                           |                                                                          |             
      Bile Duct, Hyperplasia               |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Mesentery                               |          +     +                    +              +                     |             
      Fat, Hemorrhage                      |                                     2                                    |             
      Fat, Necrosis                        |          2     2                                   2                     |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                       2  3               |             
      Inflammation, Chronic Active         |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 2| 3| 9| 1| 3| 3| 7| 3| 3| 3| 3| 3| 8| 9| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|             
                                           | 3| 4| 2| 1| 5| 2| 2| 8| 2| 3| 3| 3| 2| 6| 7| 3| 2| 3| 1| 3| 3| 5| 1| 2| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
      Duct, Cyst                           |                                                          3               |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                      1                                                   |             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
      Malformation                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |             2                                            1     2         |             
      Artery, Inflammation, Chronic Active |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 2                                                  2        2            |             
      Hypertrophy                          |                            2                                             |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                             2            |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  M  +  +  M  M  +  +  M  +  +  M  +  M  +  +  M  M  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia           |    3              2                                      3              4|             
      Pars Intermedia, Hyperplasia         |                2                                                         |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 2| 3| 9| 1| 3| 3| 7| 3| 3| 3| 3| 3| 8| 9| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|             
                                           | 3| 4| 2| 1| 5| 2| 2| 8| 2| 3| 3| 3| 2| 6| 7| 3| 2| 3| 1| 3| 3| 5| 1| 2| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |       1                                2           2                 4   |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | 2     3        3  3     2  2                          2  3  3            |             
      Thrombosis                           |                3                                                         |             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Amyloid Deposition                   |                   2                                                      |             
      Angiectasis                          |                                                                          |             
      Endometrium, Hyperplasia, Cystic     | 4  3  4  4  3  3  3  2  3  3  3  4  3  4  3  4  3  4  3  4  3  4  2  2  4|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mast Cell     |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |          +        +  +                             +           +         |             
      Iliac, Infiltration Cellular, Plasma |                                                                          |             
          Cell                             |                                                                          |             
      Renal, Ectasia                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  M  +  M  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  M  +  M  +  +  M  +  +  +  +  +  +  +  +  +  M  +  M  +  +  I  M  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +|             
      Infiltration Cellular, Mast Cell     |    2                                                                     |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 2| 3| 9| 1| 3| 3| 7| 3| 3| 3| 3| 3| 8| 9| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|             
                                           | 3| 4| 2| 1| 5| 2| 2| 8| 2| 3| 3| 3| 2| 6| 7| 3| 2| 3| 1| 3| 3| 5| 1| 2| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |       3  2                                                              2|             
      Infiltration Cellular, Mast Cell     |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                4         |             
      Inflammation, Chronic Active         |       2                          1                                       |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mast Cell     |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                      +                                                   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mast Cell     |    4                                                                     |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 2| 3| 9| 1| 3| 3| 7| 3| 3| 3| 3| 3| 8| 9| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|             
                                           | 3| 4| 2| 1| 5| 2| 2| 8| 2| 3| 3| 3| 2| 6| 7| 3| 2| 3| 1| 3| 3| 5| 1| 2| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Inflammation, Suppurative            | 1                                                                 1      |             
      Artery, Inflammation, Chronic Active |                                                                          |             
      Glands, Hyperplasia                  | 1        1                    1  1  1  1  1  1  1        1     1         |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |          1                                                               |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         | 2           1  2  2     2     1  1           2  2     2  2           2   |             
      Respiratory Epithelium, Metaplasia   |                                                                         1|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cornea, Inflammation, Chronic Active |                                                                1         |             
      Cornea, Mineralization               |                                                 1                        |             
      Retina, Atrophy                      |                                                                3         |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                               2                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Amyloid Deposition                   |                   4                                                      |             
      Metaplasia, Osseous                  | 1                                                                        |             
      Nephropathy                          |          1     1           1           3           1              1  1  1|             
      Papilla, Necrosis                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  A  +  +  +  +|  42        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  48        |
      Artery, Inflammation, Chronic Active |                                              2                           |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  47        |
      Artery, Inflammation, Chronic Active |                                              3                           |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  46        |
      Artery, Inflammation, Chronic Active |                                              2                           |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |                                                                          |      3     |
      Clear Cell Focus                     |                                                       X              X   |      3     |
      Eosinophilic Focus                   |                                                                          |      4     |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                       1  4               |      3  2.7|
      Tension Lipidosis                    |                                                                          |      1  1.0|
      Thrombosis                           |                                                 2                        |      1  2.0|
      Bile Duct, Hyperplasia               |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +        +           +  +                                +        +     +|  11        |
      Fat, Hemorrhage                      |                                                                          |      1  2.0|
      Fat, Necrosis                        | 2        2              2                                2        2     2|      9  2.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page   7                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                             3            |      3  2.7|
      Inflammation, Chronic Active         |                                                             2            |      1  2.0|
      Duct, Cyst                           |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                                                          |      1  1.0|
      Artery, Inflammation, Chronic Active |             2                                3                           |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Artery, Inflammation, Chronic Active |                                              3                 3         |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Tooth                                   |                                                             +            |   1        |
      Malformation                         |                                                             4            |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                                                          |      3  1.7|
      Artery, Inflammation, Chronic Active |             3                                                            |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                 2                        |      4  2.0|
      Hypertrophy                          |    3                             2                                       |      3  2.3|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       4                                                                  |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page   8                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  I  +  +  M  M  +  M  M  M  M  M  M  +  +  M  M  M  +|  28        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Angiectasis           |                                                                      1   |      1  1.0|
      Pars Distalis, Hyperplasia           | 2        2     2        2     2                                      2   |     10  2.4|
      Pars Intermedia, Hyperplasia         |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Hyperplasia         |                      3           1           2                           |      7  2.1|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  M  +|  45        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cyst                                 |                         2  2                 2  2                    3   |     14  2.4|
      Thrombosis                           |                                                                          |      1  3.0|
      Artery, Inflammation, Chronic Active |                                              3                           |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Amyloid Deposition                   |                                                                          |      1  2.0|
      Angiectasis                          |                                              4                           |      1  4.0|
      Endometrium, Hyperplasia, Cystic     | 4  4  3  3  2  2  3  2  4  4  3  3     4  3  4  2  3  4  3  4  4  4  2  2|     49  3.2|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                         +                    +                           |   7        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page   9                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
      Iliac, Infiltration Cellular, Plasma |                                                                          |            |
          Cell                             |                                              3                           |      1  3.0|
      Renal, Ectasia                       |                         3                                                |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M|  44        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +|  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                   3                                         2            |      5  2.4|
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  4.0|
      Inflammation, Chronic Active         |                                                                          |      2  1.5|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  10                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Artery, Inflammation, Chronic Active |                                              3                           |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar Epithelium, Hyperplasia     |                                              2                           |      1  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                     1                                    |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  4.0|
      Inflammation, Suppurative            |                                     1                       2            |      4  1.3|
      Artery, Inflammation, Chronic Active |                                              2                           |      1  2.0|
      Glands, Hyperplasia                  |    1  1  1  1  1  1           1  1                 1  1     1  1         |     23  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |    2     1                 2     2  2     1  1                           |      8  1.5|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |    3     1           2  1  2  1     3        1  2  1  2     2            |     24  1.8|
      Respiratory Epithelium, Metaplasia   |                                                             1  1         |      3  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cornea, Inflammation, Chronic Active |                                                                          |      1  1.0|
      Cornea, Mineralization               |                                                                          |      1  1.0|
      Retina, Atrophy                      |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  11                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 3| 7| 7| 7| 7| 7| 7| 7| 1| 6| 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 5| 3| 8| 0| 8| 3| 3| 3|            |
                                           | 1| 3| 3| 2| 8| 3| 2| 3| 2| 3| 1| 3| 7| 2| 2| 3| 3| 3| 2| 4| 6| 1| 2| 2| 7|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
      Hyperplasia                          |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Amyloid Deposition                   |                                                                          |      1  4.0|
      Metaplasia, Osseous                  |    1                                                                     |      2  1.0|
      Nephropathy                          | 1           1  1  2  1  1     1           1  1     1  1     1        1  1|     22  1.1|
      Papilla, Necrosis                    |          2                                                               |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Artery, Inflammation, Chronic Active |                                              3                           |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  12                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7|             
                             DAY ON TEST   | 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 8| 3| 3| 3| 3| 3| 3| 3| 3| 1| 1| 8| 3|             
                                           | 0| 3| 2| 2| 1| 2| 1| 3| 2| 3| 3| 0| 7| 3| 3| 2| 2| 1| 3| 2| 2| 5| 5| 3| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                      4   |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |          X                                                               |             
      Clear Cell Focus                     |    X                 X              X                                    |             
      Cyst                                 |                                                    4                     |             
      Eosinophilic Focus                   |          X     X              X           X     X     X                  |             
      Infarct                              |                                  X                                       |             
      Inflammation, Chronic                |                                                                          |             
      Mixed Cell Focus                     |                                     X                                    |             
      Necrosis                             |                                                                   2      |             
      Tension Lipidosis                    |                                                    2                     |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                   +                 +     +                    +         |             
      Artery, Inflammation, Chronic Active |                                                                          |             
      Fat, Necrosis                        |                   2                 2     2                    2         |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  13                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7|             
                             DAY ON TEST   | 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 8| 3| 3| 3| 3| 3| 3| 3| 3| 1| 1| 8| 3|             
                                           | 0| 3| 2| 2| 1| 2| 1| 3| 2| 3| 3| 0| 7| 3| 3| 2| 2| 1| 3| 2| 2| 5| 5| 3| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                      1   |             
      Inflammation                         |                                                                      1   |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                 1           1  1         |             
      Artery, Inflammation, Chronic Active |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                     2                                    |             
      Necrosis                             |                                  2                                       |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | M  +  +  M  +  M  +  +  M  +  +  +  M  +  M  M  +  +  M  +  M  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                2                 3                                       |             
      Pars Distalis, Hyperplasia           |                               2                 3           2           4|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                       3                  |             
      Follicular Cell, Hyperplasia         | 2                                               1                       1|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  14                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7|             
                             DAY ON TEST   | 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 8| 3| 3| 3| 3| 3| 3| 3| 3| 1| 1| 8| 3|             
                                           | 0| 3| 2| 2| 1| 2| 1| 3| 2| 3| 3| 0| 7| 3| 3| 2| 2| 1| 3| 2| 2| 5| 5| 3| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                    2                     |             
      Cyst                                 |                      2        2  2  3                    3  2  2  3      |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia, Cystic                  |                                        3                                 |             
      Inflammation, Suppurative            |                                                                          |             
      Necrosis                             |                                  3                                       |             
      Endometrium, Hyperplasia, Cystic     | 4  4  2  4  3  3  3  4  3  4  4  4  2     4  3  4  4  2  3  3  4  4  4  2|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Iliac, Ectasia                       |                                                                          |             
      Lumbar, Angiectasis                  |                                                                          |             
      Renal, Angiectasis                   |                                                                          |             
      Renal, Artery, Inflammation, Chronic |                                                                          |             
          Active                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  M  +  +  M  +  M  +  +  +  +  +  M  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  M  +  M  M  M  +  +  +  +  +  +  +  M  +|             
      Hyperplasia, Lymphoid                |                               3                                         2|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                               3                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  M  M  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +|             
      Hyperplasia, Lymphoid                |                               3                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  15                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7|             
                             DAY ON TEST   | 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 8| 3| 3| 3| 3| 3| 3| 3| 3| 1| 1| 8| 3|             
                                           | 0| 3| 2| 2| 1| 2| 1| 3| 2| 3| 3| 0| 7| 3| 3| 2| 2| 1| 3| 2| 2| 5| 5| 3| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                      3   |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                          |             
      Inflammation, Chronic Active         |                            2                       1                     |             
      Inflammation, Suppurative            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fracture                             |                                        X                                 |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                                        +                                 |             
      Inflammation, Suppurative            |                                        3                                 |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Meninges, Infiltration Cellular,     |                                                                          |             
           Mononuclear Cell                |                            2                                             |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                1           1                                4            |             
      Artery, Mineralization               |                                                                          |             
      Bronchiole, Hyperplasia              |                                           1                              |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                             2            |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  16                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7|             
                             DAY ON TEST   | 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 8| 3| 3| 3| 3| 3| 3| 3| 3| 1| 1| 8| 3|             
                                           | 0| 3| 2| 2| 1| 2| 1| 3| 2| 3| 3| 0| 7| 3| 3| 2| 2| 1| 3| 2| 2| 5| 5| 3| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Glands, Hyperplasia                  | 1  1     1     1  1     1        1  1  1  1     1     1     1  1     1  1|             
      Olfactory Epithelium, Atrophy        |                                     1                                    |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |    1              1                                1                     |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |    2  2           2        1     2                    2        2         |             
      Respiratory Epithelium, Metaplasia   |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cornea, Inflammation, Chronic Active |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                  1                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Metaplasia, Osseous                  |                                     1                                    |             
      Nephropathy                          | 1     1     2           1     1  2     1     1  1  1  1        1  3  1  1|             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  17                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  M  +  +  I  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  44        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
      Artery, Inflammation, Chronic Active |                      4                                                   |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
      Ulcer                                |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  47        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     | X                                                                        |      2     |
      Clear Cell Focus                     |    X                                                                     |      4     |
      Cyst                                 |                                                                          |      1  4.0|
      Eosinophilic Focus                   |    X     X  X  X                                         X               |     11     |
      Infarct                              |                                                                          |      1     |
      Inflammation, Chronic                |                                        1                                 |      1  1.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                                          |      1  2.0|
      Tension Lipidosis                    |                                                             1            |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |             +  +     +  +           +                             +  +   |  11        |
      Artery, Inflammation, Chronic Active |                      4                                                   |      1  4.0|
      Fat, Necrosis                        |             2  2                    2                             2  2   |      9  2.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  18                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Artery, Inflammation, Chronic Active |                      3                                                   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Artery, Inflammation, Chronic Active |                      3                                                   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                     1                                    |      2  1.0|
      Inflammation                         |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |             1        2     2                                             |      6  1.3|
      Artery, Inflammation, Chronic Active |                      3                                         2         |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |             2     2                                                      |      3  2.0|
      Necrosis                             |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |             3                    3                                       |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  M  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  M|  33        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pars Distalis, Angiectasis           |                                        2                                 |      3  2.3|
      Pars Distalis, Hyperplasia           |                   3                          2                    2  3   |      8  2.6|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  19                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  3.0|
      Follicular Cell, Hyperplasia         |             1                    2                                       |      5  1.4|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              |    +                    +                                                |   2        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  M  +  I  +  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  M|  42        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                                          |      1  2.0|
      Cyst                                 |    2                          2              2           2  2            |     13  2.2|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                     3        3                           |      2  3.0|
      Hyperplasia, Cystic                  |                                                                          |      1  3.0|
      Inflammation, Suppurative            |                                        2                                 |      1  2.0|
      Necrosis                             |                                                                          |      1  3.0|
      Endometrium, Hyperplasia, Cystic     | 4  4  3  4  3  3  2  2  4  1  4  4  4  3  3  3  3  2  4  3  4  3  4  4   |     48  3.3|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                      +                       +     +                     |   3        |
      Iliac, Ectasia                       |                      2                                                   |      1  2.0|
      Lumbar, Angiectasis                  |                                              3                           |      1  3.0|
      Renal, Angiectasis                   |                                              3                           |      1  3.0|
      Renal, Artery, Inflammation, Chronic |                                                                          |            |
          Active                           |                      3                                                   |      1  3.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  20                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  M  M  +  M  M  +  +  +  +  +  +  +  +  +  +|  41        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +|  42        |
      Hyperplasia, Lymphoid                |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|  49        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  +  +  +  +  M|  40        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                      2                                                   |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  47        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                                         3|      1  3.0|
      Inflammation, Chronic Active         |                                                                          |      2  1.5|
      Inflammation, Suppurative            |                                                                         4|      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fracture                             |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                         +                                                |   2        |
      Inflammation, Suppurative            |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  21                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Meninges, Infiltration Cellular,     |                                                                          |            |
           Mononuclear Cell                |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar Epithelium, Hyperplasia     |                   4                                         1            |      5  2.2|
      Artery, Mineralization               |                                                    3                     |      1  3.0|
      Bronchiole, Hyperplasia              |                   1                 1           1                        |      4  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                        1                                2|      3  1.7|
      Glands, Hyperplasia                  |          1  1  1  1  1  1        1  1        1     1     1  1  1     1   |     30  1.0|
      Olfactory Epithelium, Atrophy        |                                                                          |      1  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                1           1                                             |      5  1.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         | 2  2     1     3           2  1        2  1  2     2           2     3   |     19  1.9|
      Respiratory Epithelium, Metaplasia   |                      1  1                          1                     |      3  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
      Cornea, Inflammation, Chronic Active |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  22                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 7| 7| 7| 7| 7| 6| 5| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 0|            |
                             DAY ON TEST   | 9| 0| 3| 3| 3| 3| 3| 3| 1| 3| 6| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 2|            |
                                           | 8| 2| 2| 1| 1| 2| 1| 8| 5| 2| 2| 2| 3| 8| 2| 2| 3| 1| 2| 2| 2| 2| 3| 3| 1|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Metaplasia, Osseous                  |                            1                                             |      2  1.0|
      Nephropathy                          | 1  1        2  2  2  1        1  2  1        1              1     1  1   |     28  1.3|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  23                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 9| 0| 3| 3| 3| 3|             
                                           | 2| 3| 1| 2| 2| 2| 1| 3| 1| 1| 2| 0| 3| 1| 2| 3| 2| 3| 2| 5| 1| 3| 3| 1| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  I  M  +  +  +  +  +  +  +  +  +  I  +  +  +  I  +  +  +  I  +  +  M|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                                                                          |             
      Clear Cell Focus                     | X                    X        X     X                                    |             
      Eosinophilic Focus                   |                         X                 X                       X  X   |             
      Fatty Change                         |                                                                          |             
      Hematopoietic Cell Proliferation     |                                                             2            |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |                                                                          |             
      Tension Lipidosis                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                      +  +  +           +  +           +     +           +|             
      Fat, Necrosis                        |                         2  2           2  2           2                 3|             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                         4                                                |             
      Basophilic Focus                     |                                                                          |             
      Inflammation, Chronic Active         |                                                             2            |             
      Necrosis, Fatty                      |                                                                         3|             
      Duct, Cyst                           |                         4                                                |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  24                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 9| 0| 3| 3| 3| 3|             
                                           | 2| 3| 1| 2| 2| 2| 1| 3| 1| 1| 2| 0| 3| 1| 2| 3| 2| 3| 2| 5| 1| 3| 3| 1| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Metaplasia, Hepatocyte               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |          1                                1              1               |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                             3            |             
      Hyperplasia                          |                                                                          |             
      Hypertrophy                          | 2                                                                        |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                   2      |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  M  +  +  M  +  +  M  +  M  M  M  +  +  +  +  +  +  M  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                                                          |             
      Pars Distalis, Hyperplasia           | 4  3     2        3                 3     2  2                    1  2   |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |       2                 1                       1  1                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              |                                                                         +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  25                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 9| 0| 3| 3| 3| 3|             
                                           | 2| 3| 1| 2| 2| 2| 1| 3| 1| 1| 2| 0| 3| 1| 2| 3| 2| 3| 2| 5| 1| 3| 3| 1| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENERAL BODY SYSTEM - cont                |                                                                          |             
      Inflammation, Suppurative            |                                                                         3|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  M  +  +  M  +  M  +  +  M  +  +  +  M  +  I  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I|             
      Cyst                                 |             2  4  2        3     3     2        3           2            |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
      Thrombosis                           |                                                                   2      |             
      Endometrium, Hyperplasia, Cystic     | 4  4  4  4  4  1  3  4  2  4  4  1  3  2  4  2  4  4  2     2  4  4  4  3|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                  +                       +               |             
      Lumbar, Ectasia                      |                                                                          |             
      Renal, Angiectasis                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  M  +  +  +  I  M  +  M  +  +  +  +  +  M  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                         3              2                    3            |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  26                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 9| 0| 3| 3| 3| 3|             
                                           | 2| 3| 1| 2| 2| 2| 1| 3| 1| 1| 2| 0| 3| 1| 2| 3| 2| 3| 2| 5| 1| 3| 3| 1| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                  4                                       |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                         2                                                |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                      +                                                   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Meninges, Infiltration Cellular,     |                                                                          |             
           Mononuclear Cell                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Inflammation, Chronic Active |                                                                          |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                                  3                                       |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mononuclear   |                                                                          |             
          Cell                             |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                                           1                    2         |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                                                          |             
      Bronchiole, Hyperplasia              |                                                 3                    1   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                             1            |             
      Glands, Hyperplasia                  | 1     1  1  1           1                 1  1  1        1  1        1   |             
      Olfactory Epithelium, Atrophy        |                                                                          |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  27                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 9| 0| 3| 3| 3| 3|             
                                           | 2| 3| 1| 2| 2| 2| 1| 3| 1| 1| 2| 0| 3| 1| 2| 3| 2| 3| 2| 5| 1| 3| 3| 1| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
           Hyaline                         |                                  2                                       |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |          2     1        2     2           2           2     2            |             
      Respiratory Epithelium, Metaplasia   |       1                 1                    1           1  1            |             
      Respiratory Epithelium, Metaplasia,  |                                                                          |             
           Squamous                        |                                           1                              |             
      Turbinate, Necrosis                  |       2                             1                                    |             
                                           |__________________________________________________________________________|             
   Pleura                                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration, Hyaline                |                                  3                                       |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cataract                             |                                                                          |             
      Cornea, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                   3      |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Metaplasia, Osseous                  |             1                                                            |             
      Nephropathy                          |       1        1     1  1  1     2  1  1  1     1     3     1  1     1  3|             
      Artery, Inflammation, Chronic Active |          3                                                               |             
      Pelvis, Dilatation                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  28                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | I  M  A  +  I  +  I  +  I  +  +  +  +  +  A  +  A  +  +  +  +  A  +  I  +|  34        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                              2                           |      1  2.0|
      Basophilic Focus                     |                X                                                         |      1     |
      Clear Cell Focus                     |          X                                                               |      5     |
      Eosinophilic Focus                   | X              X  X                    X  X                             X|     10     |
      Fatty Change                         |                                  2                                       |      1  2.0|
      Hematopoietic Cell Proliferation     |                                  2                                       |      2  2.0|
      Mixed Cell Focus                     |                                              X                           |      1     |
      Necrosis                             |                            2     2        2     3              4         |      5  2.6|
      Tension Lipidosis                    |                                                    2              2     1|      3  1.7|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                +     +                                   +     +        +|  13        |
      Fat, Necrosis                        |                2     2                                   2     2        2|     11  2.1|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Atrophy                              |                                                                          |      1  4.0|
      Basophilic Focus                     | 2                                                                        |      1  2.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  29                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
      Inflammation, Chronic Active         |                                                                          |      1  2.0|
      Necrosis, Fatty                      |                                                                          |      1  3.0|
      Duct, Cyst                           |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                                       1                  |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  48        |
      Metaplasia, Hepatocyte               |                            4                                             |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                1                                            1            |      5  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                                                                          |      1  3.0|
      Hyperplasia                          |                                     2                                    |      1  2.0|
      Hypertrophy                          |                                        3                                3|      3  2.7|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                  2                                       |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Hyperplasia                          |                   2                                                      |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  M  +  M  M  M  +  +  +  M  M  M  M  +  +  +  M  +  M  +  A  +  +  +|  30        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +|  48        |
      Pars Distalis, Angiectasis           |    2     3              2                                                |      3  2.3|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  30                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
      Pars Distalis, Hyperplasia           |                   2  3                          2        3               |     13  2.5|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Follicular Cell, Hyperplasia         |             2        1              1           2  2           2     2   |     11  1.5|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              |                                                                          |   1        |
      Inflammation, Suppurative            |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|  41        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
      Cyst                                 | 2     3                                            2  4           2      |     13  2.6|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Angiectasis                          |                                                             4            |      1  4.0|
      Inflammation, Suppurative            |                                                 3                        |      1  3.0|
      Thrombosis                           |                                                                          |      1  2.0|
      Endometrium, Hyperplasia, Cystic     | 3  4  1  2  2  4  3  3  3  2     4  2  4     4  2  3  4  3  4     3  4  3|     46  3.1|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |          +                    +           +              +     +  +  +   |   9        |
      Lumbar, Ectasia                      |                                                          3               |      1  3.0|
      Renal, Angiectasis                   |                                                                      3   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  +  +  M  +  +  +  +  +  M  +  M  +  +  A  +  M  +  +  M  +  +  +|  39        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  M  +  M  +  +  M  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +|  39        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  31                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  M  M  +  +  M  M  +  +  +  +  +  M  +  +  M  M  +  +  +  A  +  +  +|  38        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Hematopoietic Cell Proliferation     |                         2  3     4        3                              |      7  2.9|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  46        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         | 1              1                                            2           2|      5  2.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperostosis                         |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +                                +                                       |   3        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Meninges, Infiltration Cellular,     |                                                                          |            |
           Mononuclear Cell                |             2  1                                                         |      2  1.5|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  49        |
      Artery, Inflammation, Chronic Active |                   3                                                      |      1  3.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  32                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular, Mononuclear   |                                                                          |            |
          Cell                             |                                                             4            |      1  4.0|
      Alveolar Epithelium, Hyperplasia     |                                                          2               |      3  1.7|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                            1                                3            |      2  2.0|
      Bronchiole, Hyperplasia              |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |             3                                                            |      2  2.0|
      Glands, Hyperplasia                  |    1  1     1  1  1                    1              1  1     1  1  1  1|     23  1.0|
      Olfactory Epithelium, Atrophy        |                1                                                         |      1  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |          1  2                                      1                     |      4  1.5|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |       2  2  2  1        2     1     1        2     2        2  2     2  2|     20  1.8|
      Respiratory Epithelium, Metaplasia   |                                                          1               |      6  1.0|
      Respiratory Epithelium, Metaplasia,  |                                                                          |            |
           Squamous                        |                                                                          |      1  1.0|
      Turbinate, Necrosis                  |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Pleura                                  |                                  +                                       |   1        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Degeneration, Hyaline                |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Cataract                             |                                  3                                       |      1  3.0|
      Cornea, Inflammation, Chronic Active |             2                    3                       2               |      3  2.3|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  33                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 0| 6| 7| 7| 6| 6| 5| 7| 7| 7| 7| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 4| 3| 3| 3| 3| 3| 3| 5| 7| 4| 3| 3| 8| 9| 6| 3| 3| 3| 3| 7| 3| 3| 3|            |
                                           | 2| 2| 8| 3| 2| 2| 2| 3| 3| 1| 5| 8| 2| 3| 4| 6| 7| 2| 3| 3| 2| 3| 3| 1| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Hyperplasia                          |                                                                      3   |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Cyst                                 |                   3                                                      |      1  3.0|
      Metaplasia, Osseous                  |                   1                                               1      |      3  1.0|
      Nephropathy                          | 1  1  1        1           1     1  1  1                    1        1  1|     26  1.2|
      Artery, Inflammation, Chronic Active |                                                                          |      1  3.0|
      Pelvis, Dilatation                   |                         2                                                |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  34                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 3|             
                             DAY ON TEST   | 3| 3| 1| 3| 3| 3| 3| 2| 3| 3| 2| 3| 0| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 2|             
                                           | 3| 3| 5| 3| 2| 5| 1| 4| 2| 1| 2| 1| 5| 4| 3| 9| 1| 3| 3| 2| 2| 3| 1| 3| 9|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  M  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A|             
      Peyer's Patch, Hyperplasia           |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                                                 X        X               |             
      Clear Cell Focus                     |       X                                                                  |             
      Eosinophilic Focus                   |                                  X              X  X           X  X  X   |             
      Inflammation, Chronic                | 1                 2                                                      |             
      Mixed Cell Focus                     |                                                                      X   |             
      Necrosis                             |    1                                                                     |             
                                           |__________________________________________________________________________|             
   Mesentery                               |             +                                      +                     |             
      Fat, Necrosis                        |             2                                      2                     |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                                          |             
      Inflammation                         | 2                                                                        |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  35                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 3|             
                             DAY ON TEST   | 3| 3| 1| 3| 3| 3| 3| 2| 3| 3| 2| 3| 0| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 2|             
                                           | 3| 3| 5| 3| 2| 5| 1| 4| 2| 1| 2| 1| 5| 4| 3| 9| 1| 3| 3| 2| 2| 3| 1| 3| 9|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                              1                           |             
      Inflammation, Suppurative            |                      3                                                   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                          2  1            |             
      Hypertrophy                          |             1                                                            |             
      Infiltration Cellular, Mononuclear   |                                                                          |             
          Cell                             |                                                             3            |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                               2                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  M  +  M  M  +  M  +  +  +  +  +  M  +  M  M|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Angiectasis           |                                        1                          2      |             
      Pars Distalis, Hyperplasia           | 3  2        3                                   3              3         |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         | 2           1        1     1                                             |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  36                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 3|             
                             DAY ON TEST   | 3| 3| 1| 3| 3| 3| 3| 2| 3| 3| 2| 3| 0| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 2|             
                                           | 3| 3| 5| 3| 2| 5| 1| 4| 2| 1| 2| 1| 5| 4| 3| 9| 1| 3| 3| 2| 2| 3| 1| 3| 9|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
   Clitoral Gland                          | +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  M  M  +  M  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       2     2              2        3                                    |             
      Inflammation, Suppurative            |                                                                          |             
      Artery, Inflammation, Chronic Active |                                                                          |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Infiltration Cellular, Mixed Cell    |                                                       2                  |             
      Inflammation, Suppurative            |                                                                          |             
      Metaplasia, Squamous                 |                   2                                                      |             
      Endometrium, Hyperplasia, Cystic     | 3  3  4  3  3  2  4  3  4  4  4  4  4  2  3  2  3  4  4  3  3  4  3  4  2|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |       +                                               +                  |             
      Lumbar, Infiltration Cellular,       |                                                                          |             
          Plasma Cell                      |                                                       4                  |             
      Renal, Infiltration Cellular, Plasma |                                                                          |             
          Cell                             |                                                       3                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  M  M  +  M  +  +  +  +  M  +  +  +  +  +  +  M  M  M  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  M  +  M  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Plasma Cell   |                   3                                                      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  M  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                   2                                   4                  |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  M  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  37                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 3|             
                             DAY ON TEST   | 3| 3| 1| 3| 3| 3| 3| 2| 3| 3| 2| 3| 0| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 2|             
                                           | 3| 3| 5| 3| 2| 5| 1| 4| 2| 1| 2| 1| 5| 4| 3| 9| 1| 3| 3| 2| 2| 3| 1| 3| 9|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
      Artery, Inflammation, Chronic Active |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Meninges, Infiltration Cellular,     |                                                                          |             
           Mononuclear Cell                |                                                    2                     |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                      1                                               1   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Glands, Hyperplasia                  |                   1     1           1     1     1  1  1  1     1         |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                         1                                                |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                               2                          1  1            |             
      Respiratory Epithelium, Metaplasia   |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  38                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 3|             
                             DAY ON TEST   | 3| 3| 1| 3| 3| 3| 3| 2| 3| 3| 2| 3| 0| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 2|             
                                           | 3| 3| 5| 3| 2| 5| 1| 4| 2| 1| 2| 1| 5| 4| 3| 9| 1| 3| 3| 2| 2| 3| 1| 3| 9|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |                                                                      4   |             
      Cornea, Inflammation, Chronic Active |                   3                                                      |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Metaplasia, Osseous                  |                                  1                                       |             
      Nephropathy                          |          1              3                 1  1  1  3  2        2     1   |             
      Papilla, Necrosis                    |                                                                          |             
      Renal Tubule, Hyperplasia            |                                                    2                     |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  39                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 4| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|            |
                                           | 3| 2| 1| 3| 3| 3| 3| 7| 3| 3| 3| 2| 1| 1| 7| 2| 1| 2| 1| 5| 2| 2| 3| 2| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  M  +  M  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  +  +  +  I|  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Peyer's Patch, Hyperplasia           | 2                                                                        |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |                                                                   X      |      3     |
      Clear Cell Focus                     |          X                                                               |      2     |
      Eosinophilic Focus                   |                X        X  X           X     X              X  X        X|     14     |
      Inflammation, Chronic                |                                                                          |      2  1.5|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                         +  +  +        +  +     +                        |   8        |
      Fat, Necrosis                        |                         2  2  2        2        2                        |      7  2.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                                2         |      1  2.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  40                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 4| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|            |
                                           | 3| 2| 1| 3| 3| 3| 3| 7| 3| 3| 3| 2| 1| 1| 7| 2| 1| 2| 1| 5| 2| 2| 3| 2| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                              2     2                     |      2  2.0|
      Inflammation                         |                   1                                                      |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Necrosis                             |                                                 1                        |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Tooth                                   |                                  +                                       |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                  1                 1                     |      3  1.0|
      Inflammation, Suppurative            |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      2  1.5|
      Hypertrophy                          | 1                    1                                                   |      3  1.0|
      Infiltration Cellular, Mononuclear   |                                                                          |            |
          Cell                             |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  M  M  M  M  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  I|  36        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pars Distalis, Angiectasis           |                                                                          |      2  1.5|
      Pars Distalis, Hyperplasia           | 1  3  3                 3                    2              3            |     11  2.6|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  41                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 4| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|            |
                                           | 3| 2| 1| 3| 3| 3| 3| 7| 3| 3| 3| 2| 1| 1| 7| 2| 1| 2| 1| 5| 2| 2| 3| 2| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
   Thyroid Gland                           | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Follicular Cell, Hyperplasia         |    2                 1              2                                   3|      8  1.6|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  M  M  M  +  +  +  +  +  +  +  +  +  +  +  +|  42        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |       2                 3                    2              2     2      |      9  2.2|
      Inflammation, Suppurative            |          1                                                               |      1  1.0|
      Artery, Inflammation, Chronic Active |                      3                                                   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                         3                             3                  |      2  3.0|
      Infiltration Cellular, Mixed Cell    |                                                                          |      1  2.0|
      Inflammation, Suppurative            |          4                                                               |      1  4.0|
      Metaplasia, Squamous                 |                                                                          |      1  2.0|
      Endometrium, Hyperplasia, Cystic     | 4  3  4  3  4  1  4  4  4  4  3  4     4  4  3  3  4  4  2  4  3  3  4  4|     49  3.4|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |    +                    +                                +               |   5        |
      Lumbar, Infiltration Cellular,       |                                                                          |            |
          Plasma Cell                      |                                                                          |      1  4.0|
      Renal, Infiltration Cellular, Plasma |                                                                          |            |
          Cell                             |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  M  +  M  +  +  +  +  +  +|  37        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  42                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 4| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|            |
                                           | 3| 2| 1| 3| 3| 3| 3| 7| 3| 3| 3| 2| 1| 1| 7| 2| 1| 2| 1| 5| 2| 2| 3| 2| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
   Lymph Node, Mandibular                  | M  M  +  M  +  +  M  +  +  M  +  +  M  +  +  +  +  +  +  +  +  M  +  +  M|  38        |
      Infiltration Cellular, Plasma Cell   |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +|  47        |
      Angiectasis                          | 2                                                                        |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  M  +  M  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  M  +  +|  41        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                            3     4              2                        |      5  3.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|  46        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                            4                       1                     |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                      +                    +                              |   2        |
      Artery, Inflammation, Chronic Active |                      3                                                   |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Meninges, Infiltration Cellular,     |                                                                          |            |
           Mononuclear Cell                |                   2                                                      |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  43                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 4| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|            |
                                           | 3| 2| 1| 3| 3| 3| 3| 7| 3| 3| 3| 2| 1| 1| 7| 2| 1| 2| 1| 5| 2| 2| 3| 2| 2|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar Epithelium, Hyperplasia     |                            1                    1                    1   |      5  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Glands, Hyperplasia                  |    1        1        1  1  1     1           1  1  1        1  1         |     20  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                                                                          |      1  1.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |    2  1           1     1              1  1        1  2        2        1|     13  1.3|
      Respiratory Epithelium, Metaplasia   |                                              1                           |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Degeneration                         |                                                                          |      1  4.0|
      Cornea, Inflammation, Chronic Active | 3                                                                        |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                1                                                         |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Metaplasia, Osseous                  |                                                             1            |      2  1.0|
      Nephropathy                          | 1  1        1     1  1  1  3        1  1     2  3  1  1  1     1  1  1  1|     27  1.4|
      Papilla, Necrosis                    |                                                                   2      |      1  2.0|
      Renal Tubule, Hyperplasia            |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  44                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 4| 7| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 7| 8| 3| 1| 2| 1| 3| 3| 3| 2| 3| 3| 3| 2| 3| 3| 2| 2| 2| 1| 2| 3| 3| 3|             
                                           | 9| 8| 2| 0| 4| 9| 2| 1| 1| 0| 9| 0| 1| 0| 9| 1| 0| 9| 9| 9| 8| 9| 0| 0| 0|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  A  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |             3                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Peyer's Patch, Hyperplasia           |                         3                                                |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                        2                                 |             
      Basophilic Focus                     | X        X     X           X                    X                    X  X|             
      Clear Cell Focus                     |                   X  X     X     X  X  X     X  X     X  X     X         |             
      Eosinophilic Focus                   |    X                                      X                             X|             
      Inflammation, Granulomatous          |          2                                                               |             
      Mixed Cell Focus                     |                                                                      X   |             
      Necrosis                             | 2                 2                       1        1                     |             
      Tension Lipidosis                    |                                                          1               |             
      Bile Duct, Hyperplasia               |                                                    1                     |             
      Hepatocyte, Vacuolization Cytoplasmic|                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |    +     +                       +     +                 +     +         |             
      Fat, Necrosis                        |    2     2                       2     2                 3     2         |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  45                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 4| 7| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 7| 8| 3| 1| 2| 1| 3| 3| 3| 2| 3| 3| 3| 2| 3| 3| 2| 2| 2| 1| 2| 3| 3| 3|             
                                           | 9| 8| 2| 0| 4| 9| 2| 1| 1| 0| 9| 0| 1| 0| 9| 1| 0| 9| 9| 9| 8| 9| 0| 0| 0|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
      Inflammation, Acute                  |                                                             3            |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                   3                                         2            |             
      Inflammation                         |                                                                          |             
      Ulcer                                |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Necrosis                             |                   2                                                      |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1              1              1                    2                     |             
      Thrombosis                           |                                           4                              |             
      Artery, Inflammation, Chronic Active |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                      2                    3  2        2  2     2  2  1   |             
      Hypertrophy                          |                2     2  3  2     2  2  1  4     2  2  2  2     2         |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                    2                     |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                2                                                         |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  M  M  M  +  +  M  M  +  M  +  M  +  +  +  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Hyperplasia           |                                                    4                     |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |                                                                2     1   |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                             Page  46                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 4| 7| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 7| 8| 3| 1| 2| 1| 3| 3| 3| 2| 3| 3| 3| 2| 3| 3| 2| 2| 2| 1| 2| 3| 3| 3|             
                                           | 9| 8| 2| 0| 4| 9| 2| 1| 1| 0| 9| 0| 1| 0| 9| 1| 0| 9| 9| 9| 8| 9| 0| 0| 0|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Granuloma Sperm                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |                                           2                              |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            | 3                                                                        |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Dilatation                           |                                                                          |             
      Inflammation, Chronic Active         |                      1                                                   |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Interstitial Cell, Hyperplasia       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  M  +  M  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  M  +  +  +  +  +  +  +  M  M  +  M  +  +  M  +  +  +  +  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                                   2      |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  M  M  +  M  +  +  +  +  +  +  +  I  +  +  +  M  +  +  +  M  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  47                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 4| 7| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 7| 8| 3| 1| 2| 1| 3| 3| 3| 2| 3| 3| 3| 2| 3| 3| 2| 2| 2| 1| 2| 3| 3| 3|             
                                           | 9| 8| 2| 0| 4| 9| 2| 1| 1| 0| 9| 0| 1| 0| 9| 1| 0| 9| 9| 9| 8| 9| 0| 0| 0|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |    4                                                                     |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                               2                                          |             
      Joint, Cartilage, Hyperplasia        |                                                                          |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                   +                                         +            |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                   2                                         1            |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion, Chronic                  |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |                         3                             1        2         |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                           3                              |             
      Bronchiole, Hyperplasia              |          3                                                               |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        1                                 |             
      Inflammation, Suppurative            |    1                                   1                                 |             
      Glands, Hyperplasia                  |    1     1  1        1  1     1  1  1  1  1  1  1     1  1  1  1  1  1  1|             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                                                                          |             
      Respiratory Epithelium, Metaplasia   |          1           1     1     1              1              1         |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  48                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 4| 7| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 7| 8| 3| 1| 2| 1| 3| 3| 3| 2| 3| 3| 3| 2| 3| 3| 2| 2| 2| 1| 2| 3| 3| 3|             
                                           | 9| 8| 2| 0| 4| 9| 2| 1| 1| 0| 9| 0| 1| 0| 9| 1| 0| 9| 9| 9| 8| 9| 0| 0| 0|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
   Pleura                                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Retina, Atrophy                      |                                                             3            |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                2                                                  3      |             
      Hypertrophy                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            | 3                                                                        |             
      Metaplasia, Osseous                  |                               1                                          |             
      Nephropathy                          |       2     3  1  3     1  1  1  1  1     2  1  1  1  1  1  2  1  2  1  1|             
      Renal Tubule, Hyperplasia            |                                                                1         |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         | 2                                                                        |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  49                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  M  +  +  +  +|  43        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Acute                  |                                        2                                 |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Ulcer                                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Peyer's Patch, Hyperplasia           |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                                          |      1  2.0|
      Basophilic Focus                     |                                                                X         |      8     |
      Clear Cell Focus                     | X  X     X           X        X        X  X  X  X  X                 X   |     22     |
      Eosinophilic Focus                   |                                                                          |      3     |
      Inflammation, Granulomatous          |                                                                          |      1  2.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                                         1|      5  1.4|
      Tension Lipidosis                    |                                  2              2              1         |      4  1.5|
      Bile Duct, Hyperplasia               |                                                                          |      1  1.0|
      Hepatocyte, Vacuolization Cytoplasmic|                         2                                                |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                               +              +                       +   |   9        |
      Fat, Necrosis                        |                               2              2                       2   |      9  2.1|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  50                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Acute                  |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                         3                                                |      3  2.7|
      Inflammation                         |                                                          1               |      1  1.0|
      Ulcer                                |                         2              2                                 |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                              2                           |      1  2.0|
      Necrosis                             |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                     1  1     1           2  1           1|     10  1.2|
      Thrombosis                           |                   4                                                      |      2  4.0|
      Artery, Inflammation, Chronic Active |                      2     2                                             |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                        2           2  2        2     2   |     13  2.0|
      Hypertrophy                          | 2  1  2  2  2        1                    1  2     2  2     2     2  2   |     26  2.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  51                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
   Parathyroid Gland                       | +  +  +  +  M  +  +  M  M  +  M  +  +  +  +  +  M  M  M  +  M  +  +  M  M|  32        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Hyperplasia           |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Hyperplasia         |                                           2     1                        |      4  1.5|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Granuloma Sperm                      |                                                    3  3                  |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Penis                                   |                   +                                                      |   1        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectasia                              |                         2                                                |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Dilatation                           |          3                                                               |      1  3.0|
      Inflammation, Chronic Active         |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                   2                                            3         |      2  2.5|
      Interstitial Cell, Hyperplasia       |    2                                                                     |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  52                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  M  M  M  +  +  M  +  +  M  +  +  M  +  +  +  +  M  +  +  +|  39        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  M  +  M  +  +  +  M  +  +  +  +  +  +  M  I  +  +  M  +  +  +  +  +|  37        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  M  +  +  +  +  M  +  +  +  +  M  +  +  M  M  +  +  +  +  +  +  M  +|  42        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                                                                         2|      2  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  42        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Acute                  |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperostosis                         |                                                                          |      1  2.0|
      Joint, Cartilage, Hyperplasia        |                      3                                                   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                                  +                                       |   3        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Necrosis                             |                                                                          |      2  1.5|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  53                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Congestion, Chronic                  |                   4                                                      |      1  4.0|
      Alveolar Epithelium, Hyperplasia     |                      4  1                 3                       2      |      7  2.3|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                                                          |      1  3.0|
      Bronchiole, Hyperplasia              |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  1.0|
      Inflammation, Suppurative            |    1                                                           1         |      4  1.0|
      Glands, Hyperplasia                  | 1     1           1  1     1     1     1     1     1  1        1  1  1  1|     33  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                         1                                                |      1  1.0|
      Respiratory Epithelium, Metaplasia   |          1     1     1                                                   |      9  1.0|
                                           |__________________________________________________________________________|____________|
   Pleura                                  |                                                          +               |   1        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Retina, Atrophy                      |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                              2                           |      3  2.3|
      Hypertrophy                          |                                  2                                       |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  54                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 2| 3| 2| 2| 3| 0| 3| 7| 3| 3| 6| 2| 3| 3| 2| 3| 3| 9| 2| 3| 2| 3| 3| 2|            |
                                           | 1| 9| 0| 9| 9| 1| 4| 1| 6| 0| 0| 6| 9| 1| 0| 9| 0| 0| 8| 2| 0| 9| 0| 0| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      A     |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
      Inflammation, Suppurative            |                                                                          |      1  3.0|
      Metaplasia, Osseous                  |                                        1                                 |      2  1.0|
      Nephropathy                          | 1  1  1  1  1  1  3  1     1  1     2  3     1  1  1     3  2  2  1  1  1|     41  1.4|
      Renal Tubule, Hyperplasia            |                                     1                                    |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                                                                          |      1  2.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  55                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 3| 3| 8| 3| 0| 3| 2| 6| 3| 2| 2| 2| 3| 3| 2| 3| 2| 9| 2| 2| 3| 3| 3|             
                                           | 9| 9| 1| 1| 0| 0| 4| 0| 9| 5| 0| 9| 9| 9| 1| 0| 9| 0| 9| 3| 9| 4| 0| 1| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  A  +  +  +  +  M  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular,               |                                                                          |             
          Polymorphonuclear                |                                     2                                    |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Peyer's Patch, Hyperplasia           |                                                    3                     |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                         X              X                                 |             
      Clear Cell Focus                     |                X                 X           X        X              X   |             
      Eosinophilic Focus                   |                      X     X                                             |             
      Infarct                              |                                                                          |             
      Necrosis                             |                            1                                             |             
      Tension Lipidosis                    |          2              2                 2                              |             
      Bile Duct, Cyst                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |    +                                               +                     |             
      Fat, Necrosis                        |    2                                               2                     |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                 2                        |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  56                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 3| 3| 8| 3| 0| 3| 2| 6| 3| 2| 2| 2| 3| 3| 2| 3| 2| 9| 2| 2| 3| 3| 3|             
                                           | 9| 9| 1| 1| 0| 0| 4| 0| 9| 5| 0| 9| 9| 9| 1| 0| 9| 0| 9| 3| 9| 4| 0| 1| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
      Inflammation                         |                                                 2                        |             
      Ulcer                                |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                                      1   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          2  2  2  2     2     2  2     2     2     2  2                 1|             
      Hypertrophy                          |    2  1  2  2  2              2  2  2  2     2     2  2           2  2   |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                   3                                                      |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                     2        2                           |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  +  +  M  M  +  +  +  M  +  +  M  +  +  M  M  +  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  A  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |                                                                2         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular,               |                                                                          |             
          Polymorphonuclear                |                                                                2         |             
      Inflammation, Granulomatous          |                                  3                                       |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  57                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 3| 3| 8| 3| 0| 3| 2| 6| 3| 2| 2| 2| 3| 3| 2| 3| 2| 9| 2| 2| 3| 3| 3|             
                                           | 9| 9| 1| 1| 0| 0| 4| 0| 9| 5| 0| 9| 9| 9| 1| 0| 9| 0| 9| 3| 9| 4| 0| 1| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Penis                                   |                   +                                                      |             
      Inflammation, Acute                  |                   3                                                      |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |                   3              3                                       |             
      Inflammation, Chronic Active         |    3                                                                     |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                   4                                                      |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                   4                                                      |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  +  M  A  +  M  M  +  M  +  +  +  M  M  +  +  +  +  +  +  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  +  +  A  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                      3                                                   |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  I  +  +  A  +  +  M  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  58                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 3| 3| 8| 3| 0| 3| 2| 6| 3| 2| 2| 2| 3| 3| 2| 3| 2| 9| 2| 2| 3| 3| 3|             
                                           | 9| 9| 1| 1| 0| 0| 4| 0| 9| 5| 0| 9| 9| 9| 1| 0| 9| 0| 9| 3| 9| 4| 0| 1| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |    4                                                           4         |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                          2               |             
      Hyperplasia                          |                      2                                                   |             
      Alveolar Epithelium, Hyperplasia     |    1                                1                 3                  |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |    3                                                                     |             
      Bronchiole, Hyperplasia              |       2              3                                                   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
      Glands, Hyperplasia                  |          1  1  1     1           1  1  1  2  1  1  1     1  1  1  1  1   |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                                                                          |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                                           1                              |             
      Respiratory Epithelium, Metaplasia   |       1                                   1        1  1  1               |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  59                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 3| 3| 8| 3| 0| 3| 2| 6| 3| 2| 2| 2| 3| 3| 2| 3| 2| 9| 2| 2| 3| 3| 3|             
                                           | 9| 9| 1| 1| 0| 0| 4| 0| 9| 5| 0| 9| 9| 9| 1| 0| 9| 0| 9| 3| 9| 4| 0| 1| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    450 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
   Eye                                     | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cornea, Inflammation, Acute          |                   2                                                      |             
      Cornea, Inflammation, Chronic Active |                               3                    3                     |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                   3  2                                   3               |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
      Metaplasia, Osseous                  |                                                                          |             
      Nephropathy                          | 2  1  1  1     1  1  1  1  3  2  1  1  1  1  1  2        1  1  1  1  1  2|             
      Renal Tubule, Hyperplasia            |                                  1                                       |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                   4                                                      |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  60                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 7| 3| 3| 8| 3| 3| 2| 3| 3| 3| 3| 3| 2| 6| 3| 3| 3| 2| 2| 2|            |
                                           | 9| 9| 9| 9| 1| 0| 1| 0| 2| 1| 0| 9| 0| 0| 1| 1| 0| 9| 1| 0| 0| 0| 9| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  A  I  +  +  +  +  +|  44        |
      Infiltration Cellular,               |                                                                          |            |
          Polymorphonuclear                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
      Peyer's Patch, Hyperplasia           |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |             X                             X     X                        |      5     |
      Clear Cell Focus                     | X     X           X  X     X                    X           X        X   |     13     |
      Eosinophilic Focus                   |          X                       X                                       |      4     |
      Infarct                              |                               4                                          |      1  4.0|
      Necrosis                             |                                                                          |      1  1.0|
      Tension Lipidosis                    |                                                                          |      3  2.0|
      Bile Duct, Cyst                      |                                                                         X|      1     |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                       +                  |   3        |
      Fat, Necrosis                        |                                                       2                  |      3  2.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  61                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 7| 3| 3| 8| 3| 3| 2| 3| 3| 3| 3| 3| 2| 6| 3| 3| 3| 2| 2| 2|            |
                                           | 9| 9| 9| 9| 1| 0| 1| 0| 2| 1| 0| 9| 0| 0| 1| 1| 0| 9| 1| 0| 0| 0| 9| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia, Squamous                | 3                                                                    3   |      3  2.7|
      Inflammation                         | 2                                                                        |      2  2.0|
      Ulcer                                |                         3                                                |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |          1  1                                1  1  1  1        1         |      8  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       2     2              2              2  2     2                     |     18  1.9|
      Hypertrophy                          |       2     2  1  2  2        2  2     2     2  2     2  2     2  2  2  2|     30  1.9|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  M  +  +  +  +  +  M  +  +  M  +  +  M  +  +  M  M  +  M  M  +  +  M|  33        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Follicular Cell, Hyperplasia         |                   3              2                       1               |      4  2.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  62                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 7| 3| 3| 8| 3| 3| 2| 3| 3| 3| 3| 3| 2| 6| 3| 3| 3| 2| 2| 2|            |
                                           | 9| 9| 9| 9| 1| 0| 1| 0| 2| 1| 0| 9| 0| 0| 1| 1| 0| 9| 1| 0| 0| 0| 9| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infiltration Cellular,               |                                                                          |            |
          Polymorphonuclear                |                                                                          |      1  2.0|
      Inflammation, Granulomatous          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Penis                                   |                                                                          |   1        |
      Inflammation, Acute                  |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectasia                              | 3                                                                        |      3  3.0|
      Inflammation, Chronic Active         |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Suppurative            |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                            2                                   2         |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  M  +  M  +  +  +  +  +  +  +  M  +  +  +  M  M  +  M  +  +  +|  35        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  M  M  M  +  +  +  +  +  +  +  +  M  +  M  +  +  +  M  M  M  +  +  +|  36        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  M  M  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  M|  38        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  63                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 7| 3| 3| 8| 3| 3| 2| 3| 3| 3| 3| 3| 2| 6| 3| 3| 3| 2| 2| 2|            |
                                           | 9| 9| 9| 9| 1| 0| 1| 0| 2| 1| 0| 9| 0| 0| 1| 1| 0| 9| 1| 0| 0| 0| 9| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hematopoietic Cell Proliferation     |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  44        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                                                                          |      2  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                +        +                                                |   2        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  2.0|
      Hyperplasia                          |                                                                          |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |                   3        3                                             |      5  2.2|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                                                          |      1  3.0|
      Bronchiole, Hyperplasia              |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  64                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 7| 3| 3| 8| 3| 3| 2| 3| 3| 3| 3| 3| 2| 6| 3| 3| 3| 2| 2| 2|            |
                                           | 9| 9| 9| 9| 1| 0| 1| 0| 2| 1| 0| 9| 0| 0| 1| 1| 0| 9| 1| 0| 0| 0| 9| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|      A     |
    450 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                              1                           |      1  1.0|
      Glands, Hyperplasia                  | 1                 1     1  1  1  1     1  1  1  1  1  1  1  1  1     1   |     32  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                                     1                                    |      1  1.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |                                                                          |      1  1.0|
      Respiratory Epithelium, Metaplasia   | 1                          1  1        1     1                          1|     11  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
      Cornea, Inflammation, Acute          |                                                                          |      1  2.0|
      Cornea, Inflammation, Chronic Active |                                                                          |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                   2                                                      |      4  2.5|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                1                                                         |      1  1.0|
      Metaplasia, Osseous                  |                                  1                                1      |      2  1.0|
      Nephropathy                          | 3  1  1  3  1  1  2  1     2  1  1  1  1  3  1  1  2  3  1  1  2  1     2|     45  1.4|
      Renal Tubule, Hyperplasia            |                                                                         2|      2  1.5|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Suppurative            |                                                                          |      1  4.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  65                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 7| 5| 7| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6|             
                             DAY ON TEST   | 3| 1| 2| 0| 3| 3| 3| 8| 2| 3| 3| 5| 3| 2| 3| 2| 9| 3| 3| 3| 3| 7| 3| 3| 0|             
                                           | 0| 2| 9| 1| 0| 9| 1| 0| 9| 0| 1| 4| 1| 9| 0| 9| 8| 0| 0| 0| 0| 1| 0| 0| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  A  +  +  +  +  +  M  I  +  +  A  +  +  +  M  +  M  +  +  +  +  +  +  A|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                2         |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                3         |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  I  +  A|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A|             
      Peyer's Patch, Hyperplasia           |                            3              2                              |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |       X     X                                                            |             
      Clear Cell Focus                     |                   X     X     X     X     X  X        X  X           X   |             
      Eosinophilic Focus                   |                   X     X                                   X            |             
      Hepatodiaphragmatic Nodule           |                                                    X                     |             
      Inflammation, Granulomatous          |       2                                                                  |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |                                                                          |             
      Tension Lipidosis                    |    1     1                                                     2         |             
      Thrombosis                           |                                                                          |             
      Hepatocyte, Vacuolization Cytoplasmic|          2                       1                                       |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                        +  +                              |             
      Fat, Necrosis                        |                                        2  2                              |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  66                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 7| 5| 7| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6|             
                             DAY ON TEST   | 3| 1| 2| 0| 3| 3| 3| 8| 2| 3| 3| 5| 3| 2| 3| 2| 9| 3| 3| 3| 3| 7| 3| 3| 0|             
                                           | 0| 2| 9| 1| 0| 9| 1| 0| 9| 0| 1| 4| 1| 9| 0| 9| 8| 0| 0| 0| 0| 1| 0| 0| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                      1                                                  2|             
      Inflammation                         |                      2                                                  1|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
      Malformation                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 2                                               2                        |             
      Thrombosis                           |                                                 4                        |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |       2              2  2              2                 3     2  2      |             
      Hypertrophy                          |       2  2  2           2  2  2     2     1        2  2     1  1     2   |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1     2                                                                  |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | M  M  +  M  M  +  +  M  +  +  +  M  +  +  M  +  +  +  M  M  M  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  I  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Hyperplasia           |                         2                                      2         |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |                               1                          2  1           1|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  67                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 7| 5| 7| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6|             
                             DAY ON TEST   | 3| 1| 2| 0| 3| 3| 3| 8| 2| 3| 3| 5| 3| 2| 3| 2| 9| 3| 3| 3| 3| 7| 3| 3| 0|             
                                           | 0| 2| 9| 1| 0| 9| 1| 0| 9| 0| 1| 4| 1| 9| 0| 9| 8| 0| 0| 0| 0| 1| 0| 0| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Granuloma Sperm                      |                                                    2                     |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |             2                                      1              1      |             
      Thrombosis                           |                                                                2         |             
      Interstitial Cell, Hyperplasia       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                   +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  M  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                             3            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  +  +  +  +  M  M  M  M  +  A  +  +  +  +  +  M  M  M  +  +  +  M  M|             
      Hyperplasia, Lymphoid                |                                                             3            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  M  +  M  M  M  M  M  +  +  +  +  +  +  +  +  M  +  +  +|             
      Hyperplasia, Lymphoid                |                                                             3            |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                        3                                 |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  M  +  +  +  +  +  M  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  68                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 7| 5| 7| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6|             
                             DAY ON TEST   | 3| 1| 2| 0| 3| 3| 3| 8| 2| 3| 3| 5| 3| 2| 3| 2| 9| 3| 3| 3| 3| 7| 3| 3| 0|             
                                           | 0| 2| 9| 1| 0| 9| 1| 0| 9| 0| 1| 4| 1| 9| 0| 9| 8| 0| 0| 0| 0| 1| 0| 0| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                      4                                                   |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hydrocephalus                        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                    3                     |             
      Pigmentation                         |                                                                          |             
      Thrombosis                           |                                                 4                        |             
      Alveolar Epithelium, Hyperplasia     |                   3     1                                   1            |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                                                          |             
      Bronchiole, Hyperplasia              |                                                                   1  1   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
      Glands, Hyperplasia                  |    1  1     1  1     1  1  1        1        1           2  1     1     1|             
      Olfactory Epithelium, Atrophy        |                                                                          |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                                                          2               |             
      Olfactory Epithelium, Necrosis       |                                                          2               |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                                                          2               |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  69                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 7| 4| 7| 5| 7| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 6|             
                             DAY ON TEST   | 3| 1| 2| 0| 3| 3| 3| 8| 2| 3| 3| 5| 3| 2| 3| 2| 9| 3| 3| 3| 3| 7| 3| 3| 0|             
                                           | 0| 2| 9| 1| 0| 9| 1| 0| 9| 0| 1| 4| 1| 9| 0| 9| 8| 0| 0| 0| 0| 1| 0| 0| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    900 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Respiratory Epithelium, Hyperplasia  |                                                          2               |             
      Respiratory Epithelium, Metaplasia   | 1           1  1                                         2        1      |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                    3                     |             
      Inflammation, Suppurative            |                                                                          |             
      Metaplasia, Osseous                  |          1                 1                                             |             
      Nephropathy                          | 3  1     1  1  1     2  2  1  1     1  1  4  1  1  4  1  1  1     1  1  4|             
      Renal Tubule, Hyperplasia            |                      2                                                   |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  70                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  M  A  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +|  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemorrhage                           |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Hemorrhage                           |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Peyer's Patch, Hyperplasia           |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |          X                                   X                           |      4     |
      Clear Cell Focus                     | X              X           X                             X               |     13     |
      Eosinophilic Focus                   |       X                                         X                        |      5     |
      Hepatodiaphragmatic Nodule           |                                                                          |      1     |
      Inflammation, Granulomatous          |                                                                          |      1  2.0|
      Mixed Cell Focus                     |                X                                                         |      1     |
      Necrosis                             |                               3                                4         |      2  3.5|
      Tension Lipidosis                    |                                                                          |      3  1.3|
      Thrombosis                           |                                                                3         |      1  3.0|
      Hepatocyte, Vacuolization Cytoplasmic|                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |          +                                                               |   3        |
      Fat, Necrosis                        |          2                                                               |      3  2.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  71                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|  48        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia, Squamous                |                                                                          |      2  1.5|
      Inflammation                         |                                                             1            |      3  1.3|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Necrosis                             |                      2                                                   |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Tooth                                   |                                                                   +      |   1        |
      Malformation                         |                                                                   4      |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                                                          |      2  2.0|
      Thrombosis                           |                               2                    3                     |      3  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          | 2        2     2           2              2                             2|     13  2.1|
      Hypertrophy                          | 2  2  2     1                    2     1  2  2  2        1     2  2     2|     26  1.8|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                               2                                          |      3  1.7|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  I  +  M  M  +  I  +  M  M  M  +  +  +  +  M  +  +  M  M  +  +  +|  29        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  72                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Pars Distalis, Hyperplasia           |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Hyperplasia         |                                     1                                3   |      6  1.5|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Granuloma Sperm                      |                                                    1                     |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                                          |      3  1.3|
      Thrombosis                           |                                                                          |      1  2.0|
      Interstitial Cell, Hyperplasia       |                                  1                                       |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  M  M  M  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  M  M  +|  37        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  73                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
   Lymph Node, Mandibular                  | M  M  +  +  +  +  M  +  +  M  +  +  +  M  +  +  +  +  +  +  +  M  M  +  +|  32        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  M  +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  M  M|  36        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hematopoietic Cell Proliferation     |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +|  44        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Chronic Active         |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hydrocephalus                        |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  74                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |                                                                          |      1  3.0|
      Pigmentation                         |                                                 3                        |      1  3.0|
      Thrombosis                           |                                                                          |      1  4.0|
      Alveolar Epithelium, Hyperplasia     |                                     3           3                        |      5  2.2|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                              3  4  3                     |      3  3.3|
      Bronchiole, Hyperplasia              |             1                                                            |      3  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                                 2        1  3            |      3  2.0|
      Glands, Hyperplasia                  |    1     1  1     1              1     1  1  1  1                 1  1   |     24  1.0|
      Olfactory Epithelium, Atrophy        |                                                             1            |      1  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                                                       2                  |      2  2.0|
      Olfactory Epithelium, Necrosis       |                                                                          |      1  2.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |                   1                 1                                    |      3  1.3|
      Respiratory Epithelium, Hyperplasia  |                                                                          |      1  2.0|
      Respiratory Epithelium, Metaplasia   |          1  1  1                          1  1  1        1           1   |     13  1.1|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Degeneration                         |                                                             2            |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          | 3                                                                        |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  75                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 0| 7| 5| 5| 5| 7| 7|            |
                             DAY ON TEST   | 3| 3| 2| 2| 3| 2| 3| 2| 3| 3| 0| 2| 3| 2| 2| 5| 3| 1| 2| 2| 2| 1| 2| 2| 2|            |
                                           | 0| 0| 9| 9| 0| 9| 1| 9| 1| 1| 1| 9| 0| 9| 9| 9| 0| 7| 6| 9| 0| 9| 0| 9| 9|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|      A     |
    900 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
      Cyst                                 |                                                                          |      1  3.0|
      Inflammation, Suppurative            |                                                    2                     |      1  2.0|
      Metaplasia, Osseous                  |          1                                                               |      3  1.0|
      Nephropathy                          | 2  1     1  1  1  3  2  1  1  2  1  1  1  1  1  1  3     1        1      |     40  1.5|
      Renal Tubule, Hyperplasia            |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  76                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 1| 2| 3| 3| 3| 5| 3| 3| 2| 3| 1| 0| 3| 3| 2| 2| 3| 2| 2| 3| 3| 2| 3| 3|             
                                           | 1| 0| 9| 1| 1| 0| 1| 0| 0| 9| 0| 7| 7| 0| 0| 9| 9| 7| 9| 9| 1| 0| 9| 0| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  M  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Acute                  |       3                                                                  |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                            X  X  X  X        X        X                  |             
      Clear Cell Focus                     |       X           X     X     X     X  X  X  X              X  X  X  X   |             
      Eosinophilic Focus                   |                      X                    X                 X     X      |             
      Inflammation, Chronic                |                                        1                                 |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |    3              2                                               1      |             
      Tension Lipidosis                    |                      2                                                   |             
      Hepatocyte, Erythrophagocytosis      |                                                                          |             
      Hepatocyte, Vacuolization Cytoplasmic| 3                                                                        |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                     +                          +     +   |             
      Fat, Necrosis                        |                                                                2     2   |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  77                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 1| 2| 3| 3| 3| 5| 3| 3| 2| 3| 1| 0| 3| 3| 2| 2| 3| 2| 2| 3| 3| 2| 3| 3|             
                                           | 1| 0| 9| 1| 1| 0| 1| 0| 0| 9| 0| 7| 7| 0| 0| 9| 9| 7| 9| 9| 1| 0| 9| 0| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                    2                     |             
      Ulcer                                | 1                 3                                                      |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |    1                                                                    1|             
      Inflammation, Suppurative            | 3                                                                        |             
      Thrombosis                           |                                                    3                     |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |             4                                            2           2   |             
      Hypertrophy                          |          2                                   2  1                        |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  M  +  +  +  +  +  +  +  M  +  +  M  M  +  M  M  +  M  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Hyperplasia         |          3                                                  1           1|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Granuloma Sperm                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  78                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 1| 2| 3| 3| 3| 5| 3| 3| 2| 3| 1| 0| 3| 3| 2| 2| 3| 2| 2| 3| 3| 2| 3| 3|             
                                           | 1| 0| 9| 1| 1| 0| 1| 0| 0| 9| 0| 7| 7| 0| 0| 9| 9| 7| 9| 9| 1| 0| 9| 0| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Penis                                   |                                                                          |             
      Inflammation, Acute                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ectasia                              |                                                       3                  |             
      Inflammation, Chronic Active         |                                                                         2|             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic Active         |                                                                          |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Interstitial Cell, Hyperplasia       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |    +                                                                     |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  M  +  +  M  +  M  +  +  +  M  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  +  M  +  M  +  M  M  +  M  +  +  +  M  +  +  M  +  M  +  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Histiocyte    |       2                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  M  M  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                                          |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  79                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 1| 2| 3| 3| 3| 5| 3| 3| 2| 3| 1| 0| 3| 3| 2| 2| 3| 2| 2| 3| 3| 2| 3| 3|             
                                           | 1| 0| 9| 1| 1| 0| 1| 0| 0| 9| 0| 7| 7| 0| 0| 9| 9| 7| 9| 9| 1| 0| 9| 0| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Bronchiole, Hyperplasia              |          1                                                               |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            | 4                                                                       1|             
      Glands, Hyperplasia                  |       1     1  1  1        1  1  1  1     1  1              1  1     1  1|             
      Respiratory Epithelium, Metaplasia   |             1     1                          1           1           1   |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cataract                             |                      2                                                   |             
      Degeneration                         |                                                                          |             
      Cornea, Mineralization               |                                                                   1      |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                              1                           |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  80                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 _____________________________________________________________________________________________________________________              
                                           | 4| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 4| 1| 2| 3| 3| 3| 5| 3| 3| 2| 3| 1| 0| 3| 3| 2| 2| 3| 2| 2| 3| 3| 2| 3| 3|             
                                           | 1| 0| 9| 1| 1| 0| 1| 0| 0| 9| 0| 7| 7| 0| 0| 9| 9| 7| 9| 9| 1| 0| 9| 0| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    1800 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            | 2                 3                                                      |             
      Metaplasia, Osseous                  |                                                                          |             
      Nephropathy                          |    4  1  1  1  1     1  1  1  1  1  2  1  2  1  1  3  1  1  2  1  1  1  1|             
                                           |__________________________________________________________________________|             
   Ureter                                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                   3                                                      |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  81                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 1| 2| 9| 3| 1| 2| 2| 2| 2| 3| 7| 3| 2| 3| 2| 2| 3| 5| 0| 3| 2| 3|            |
                                           | 1| 1| 0| 7| 9| 3| 0| 3| 9| 9| 5| 9| 0| 8| 1| 9| 1| 9| 9| 0| 6| 1| 0| 9| 0|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  I  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
      Cyst                                 |                                                                   2      |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
      Inflammation, Acute                  |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                            2                                             |      1  2.0|
      Basophilic Focus                     |                                                                X        X|      8     |
      Clear Cell Focus                     |                   X     X  X     X  X                 X  X  X            |     20     |
      Eosinophilic Focus                   |    X              X                 X                             X      |      8     |
      Inflammation, Chronic                |                                                                          |      1  1.0|
      Mixed Cell Focus                     |                                     X                                    |      1     |
      Necrosis                             |                      2        3  2                       1               |      7  2.0|
      Tension Lipidosis                    |                                                                          |      1  2.0|
      Hepatocyte, Erythrophagocytosis      |                                                          1               |      1  1.0|
      Hepatocyte, Vacuolization Cytoplasmic|                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                             +            |   4        |
      Fat, Necrosis                        |                                                             2            |      3  2.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  82                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 1| 2| 9| 3| 1| 2| 2| 2| 2| 3| 7| 3| 2| 3| 2| 2| 3| 5| 0| 3| 2| 3|            |
                                           | 1| 1| 0| 7| 9| 3| 0| 3| 9| 9| 5| 9| 0| 8| 1| 9| 1| 9| 9| 0| 6| 1| 0| 9| 0|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                                                          |      1  2.0|
      Ulcer                                |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       | 1  1  1     1  1                    1              1        2            |     10  1.1|
      Inflammation, Suppurative            |                                                                          |      1  3.0|
      Thrombosis                           |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       2        2        1  2     2                 2                     |      9  2.1|
      Hypertrophy                          |    1  2                 2        2     2        2  2  2  2           2  2|     14  1.9|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                    2                     |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  I  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  M|  37        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Hyperplasia         |                   1           1                 2  3                 2   |      8  1.8|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  83                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 1| 2| 9| 3| 1| 2| 2| 2| 2| 3| 7| 3| 2| 3| 2| 2| 3| 5| 0| 3| 2| 3|            |
                                           | 1| 1| 0| 7| 9| 3| 0| 3| 9| 9| 5| 9| 0| 8| 1| 9| 1| 9| 9| 0| 6| 1| 0| 9| 0|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Granuloma Sperm                      |                                                                         3|      1  3.0|
                                           |__________________________________________________________________________|____________|
   Penis                                   |                                        +                                 |   1        |
      Inflammation, Acute                  |                                        4                                 |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ectasia                              |                                                                          |      1  3.0|
      Inflammation, Chronic Active         |                3                                                         |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic Active         |             2                                                            |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                        2                                 |      1  2.0|
      Interstitial Cell, Hyperplasia       | 3                                                     1                  |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                   +      |   2        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  M  +  M  +  +  +  +  M  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  39        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|  34        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Infiltration Cellular, Histiocyte    |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  +  +  I  +  +  M  M  +  +  +  +  M  +  +  +  M  +  +  M|  38        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  84                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 1| 2| 9| 3| 1| 2| 2| 2| 2| 3| 7| 3| 2| 3| 2| 2| 3| 5| 0| 3| 2| 3|            |
                                           | 1| 1| 0| 7| 9| 3| 0| 3| 9| 9| 5| 9| 0| 8| 1| 9| 1| 9| 9| 0| 6| 1| 0| 9| 0|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hematopoietic Cell Proliferation     | 2                    3        3                                          |      3  2.7|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  47        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                             3            |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar Epithelium, Hyperplasia     |                                                                   2     1|      2  1.5|
      Bronchiole, Hyperplasia              |                                  1                                       |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                                                          |      2  2.5|
      Glands, Hyperplasia                  |             1              1     1  1  1  1  1  1  1        1  1     1   |     26  1.0|
      Respiratory Epithelium, Metaplasia   |                                        1                                 |      6  1.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  85                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-02                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 04/29/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 07:49:48    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 1| 2| 9| 3| 1| 2| 2| 2| 2| 3| 7| 3| 2| 3| 2| 2| 3| 5| 0| 3| 2| 3|            |
                                           | 1| 1| 0| 7| 9| 3| 0| 3| 9| 9| 5| 9| 0| 8| 1| 9| 1| 9| 9| 0| 6| 1| 0| 9| 0|            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|      T     |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|      A     |
    1800 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
      Cataract                             |                                                                          |      1  2.0|
      Degeneration                         |             3                                                            |      1  3.0|
      Cornea, Mineralization               |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                 3                        |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |    3                                                                     |      3  2.7|
      Metaplasia, Osseous                  |                                                    1                     |      1  1.0|
      Nephropathy                          | 3     3  1  1  2        1  1  1  1  1  1  1  1  1  1  2  1  1  2        1|     43  1.3|
                                           |__________________________________________________________________________|____________|
   Ureter                                  |                         +                                                |   1        |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  86                                                               
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
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